Stockholder's Equity and Stock Based Compensation (Details2) (MSU's, Executive Officers, USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2015 item
Valuation assumptions
Expected term	3 years
Risk-free interest rate (as a percent)	0.99%
Expected volatility (as a percent)	39.00%
Expected dividend rate (as a percent)	0.00%
Number of shares underlying MSU's
Granted to employees (in shares)	240
Balance at the end of the period (in shares)	240
Average Grant Date Fair Value
Granted (in dollars per share)	$ 37.53
Balance at the end of the period (in dollars per share)	$ 37.53
Weighted average remaining vesting period (in years)
Balance at the beginning of the period (in years)	1 year 10 months 17 days
Balance at the end of the period (in years)	1 year 10 months 17 days
Aggregate Intrinsic Value
Balance at the end of the period (in dollars)	$ 6,144
Additional information
Number of separate tranches	3
Vesting period	1 year 10 months 17 days
Closing stock price (in dollars per share)	$ 25.62
Tranche one
Additional information
Percent of shares in tranche that can be received	100.00%
Grant date fair value per share	$ 9.10
Tranche two
Additional information
Percent of shares in tranche that can be received	100.00%
Grant date fair value per share	$ 8.68
Tranche three
Additional information
Percent of shares in tranche that can be received	150.00%
Grant date fair value per share	$ 19.75
Minimum
Additional information
Vesting period for each tranche (in years)	1 year
Maximum
Additional information
Vesting period for each tranche (in years)	3 years