Stock Option Plans - Restricted Stock Awards and Restricted Stock Units (Details) (USD $)	12 Months Ended			0 Months Ended	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 01, 2011 Restricted stock awards	Dec. 31, 2013 Restricted stock awards Sonar Limited	Dec. 31, 2013 Restricted stock units	Dec. 31, 2012 Restricted stock units	Dec. 31, 2011 Restricted stock units	Dec. 31, 2013 Restricted Stock Shares Restricted stock awards Sonar Limited
Nonvested Shares Subject to Performance Based Awards, Number of Shares
Number of Shares, Outstanding at December 31, 2012						425,000
Number of Shares, Granted				7,500		173,000			31,164
Number of Shares, Forfeited						(2,000)
Number of Shares, Vested						(214,000)
Number of Shares, Outstanding at December 31, 2013						382,000	425,000
Nonvested Shares Subject to Performance Based Awards, Weighted Average Grant Date Fair Value
Weighted Average Grant Date Fair Value, Outstanding at December 31, 2012 (in usd per share)						$ 14.37
Weighted Average Grant Date Fair Value, Granted (in usd per share)						$ 42.90
Weighted Average Grant Date Fair Value, Forfeited (in usd per share)						$ 40.03
Weighted Average Grant Date Fair Value, Vested (in usd per share)						$ 13.15
Weighted Average Grant Date Fair Value, Outstanding at December 31, 2013 (in usd per share)						$ 27.81	$ 14.37
Additional Information
Aggregated grant date fair value				$ 100,000					$ 700,000
Award vesting period					2 years
Vested awards					18,698
Compensation expense recognized	20,840,000	12,207,000	4,502,000			3,400,000	1,700,000	600,000
Unrecognized compensation expense related to nonvested restricted stock units						$ 8,700,000
Unrecognized compensation expense, weighted-average period of recognition						2 years 3 months