|
Stock-Based Compensation Expense (Details) (USD $)
|
1 Months Ended | 3 Months Ended | 9 Months Ended | 0 Months Ended | 1 Months Ended | 11 Months Ended | 12 Months Ended | 9 Months Ended | 9 Months Ended | 12 Months Ended | 9 Months Ended | 12 Months Ended | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Apr. 30, 2010
|
Dec. 31, 2012
|
Dec. 31, 2011
|
Dec. 31, 2012
|
Jul. 28, 2010
Restricted Stock and Stock Option Plan [Member]
|
Jul. 28, 2010
2011 Long-term Incentive Plan [Member]
|
May 05, 2011
IPO [Member]
|
Apr. 30, 2010
Stock Options [Member]
|
Mar. 31, 2011
Stock Options [Member]
|
Mar. 31, 2013
Stock Options [Member]
|
Mar. 31, 2012
Stock Options [Member]
|
Dec. 31, 2012
Stock Options [Member]
Maximum [Member]
|
May 05, 2011
Stock Options [Member]
IPO [Member]
|
Mar. 31, 2013
Restricted Stock [Member]
|
Dec. 31, 2012
Performance Shares [Member]
Executive_Officers
|
Mar. 31, 2013
Performance Shares [Member]
|
Dec. 31, 2012
Performance Shares [Member]
Minimum [Member]
|
Dec. 31, 2012
Performance Shares [Member]
Maximum [Member]
|
Mar. 31, 2013
Predecessor [Member]
Restricted Stock [Member]
|
Mar. 31, 2012
Predecessor [Member]
Restricted Stock [Member]
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||||||||||||||||||
| Intrinsic value of stock options exercised | $ 18,387,000 | $ 8,860,000 | ||||||||||||||||||
| Maximum number of shares of the company's common stock that may be awarded | 2,767,171 | 2,893,341 | ||||||||||||||||||
| Options, vested and exercisable (in shares) | 2,757,524 | |||||||||||||||||||
| Stock compensation expense associated with the acceleration of the pre-IPO options | 6,310,000 | |||||||||||||||||||
| Vesting period (in years) | 5 years | |||||||||||||||||||
| Annual vesting percentage | 20.00% | |||||||||||||||||||
| Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] | ||||||||||||||||||||
| Options outstanding, beginning of period (in shares) | 0 | 0 | 2,179,625 | 2,757,524 | ||||||||||||||||
| Granted (in shares) | 0 | 2,757,524 | 56,532 | 117,600 | ||||||||||||||||
| Exercised (in shares) | 0 | 0 | (1,086,486) | (683,443) | (8,068,000) | 0 | ||||||||||||||
| Forfeited (in shares) | 0 | 0 | (16,891) | (12,056) | 0 | 0 | ||||||||||||||
| Options outstanding, end of period (in shares) | 0 | 2,757,524 | 1,132,780 | 2,179,625 | ||||||||||||||||
| Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward] | ||||||||||||||||||||
| Options outstanding, weighted average exercise price, beginning of period (in dollars per share) | $ 0.00 | $ 0.00 | $ 5.74 | $ 5.38 | ||||||||||||||||
| Granted, weighted average exercise price (in dollars per share) | $ 0.00 | $ 5.38 | $ 21.52 | $ 12.00 | $ 21.52 | $ 12.42 | ||||||||||||||
| Exercised, weighted average exercise price (in dollars per share) | $ 0.00 | $ 0.00 | $ 5.31 | $ 5.38 | $ 12.42 | $ 0.00 | ||||||||||||||
| Forfeited, weighted average exercise price (in dollars per share) | $ 0.00 | $ 0.00 | $ 7.98 | $ 6.46 | $ 0.00 | $ 0.00 | ||||||||||||||
| Options outstanding, weighted average exercise price, end of period (in dollars per share) | $ 0.00 | $ 5.38 | $ 6.98 | $ 5.74 | ||||||||||||||||
| Stock compensation expense | 0 | 1,341,000 | 1,939,000 | 6,514,000 | ||||||||||||||||
| Closing price (in dollars per share) | $ 22.21 | |||||||||||||||||||
| Aggregate intrinsic value | 468,187,000 | |||||||||||||||||||
| Total unrecognized expense related to non-vested stock option awards | 1,053,000 | 130,363,000 | 438,000 | |||||||||||||||||
| Stock based compensation, recognition period | 3 years 6 months 4 days | |||||||||||||||||||
| Number of executives issued stock | 4 | |||||||||||||||||||
| Total fair value of options issued | $ 960,000 | |||||||||||||||||||
| Expiration term | 10 years | |||||||||||||||||||
| Amortization Period For The Fair Value Share Based Compsensation Award (in years) | 3 years | |||||||||||||||||||
| Possible number of shares issued each year | 0 | 29,430 | ||||||||||||||||||