Stock-Based Compensation (Details) (USD $)	3 Months Ended			3 Months Ended		12 Months Ended	1 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014 RSAs	Mar. 31, 2014 RSAs Performance-contingent	Mar. 31, 2014 RSAs Performance-contingent 2011 Restricted Stock Awards	Dec. 31, 2011 RSAs Performance-contingent 2011 Restricted Stock Awards	May 31, 2014 RSAs Performance-contingent 2011 Restricted Stock Awards Subsequent events	Mar. 31, 2014 2012 Equity Incentive Plan
Stock-based compensation
Shares remaining available for issuance								2,925,115
Period for which compensation committee has approved grants				3 years
Shares of common stock approved and authorized for issuance						1,290,000
Timeframe for achievement of performance conditions						6 years
Maximum potential expense, net of forfeiture			$ 21,900,000			$ 28,200,000
Stock-based compensation expense	13,535,000	6,095,000			6,800,000
Total stock-based compensation that will be recognized in the year					7,000,000
Stock-based compensation expenses that will be recognized subject to sufficient performance conditions							$ 4,300,000
Vesting period							1 year