Convertible Senior Notes - Additional Information (Details) - USD ($) $ / shares in Units, shares in Millions	1 Months Ended	12 Months Ended
	May. 31, 2013	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Schedule of Convertible Senior Notes
Stock repurchased and retired during period, shares	0.6	4.9	2.0	0.1
Common stock repurchased and retired	$ 30,000,000
Strike price of warrants	$ 83.18
Proceeds from issuance of warrants	$ 43,600,000	$ 0	$ 0	$ 43,560,000
Convertible Senior Notes Zero Point Two Five Percentage Due May Fifteen Two Thousand And Eighteen | Convertible Senior Notes
Schedule of Convertible Senior Notes
Convertible senior notes, face amount		$ 300,000,000	$ 300,000,000
Contractual interest rate		0.25%
Maturity date		May 15, 2018
Conversion rate		15.5847
Denomination amount		$ 1,000
Conversion price		$ 64.17
Number of days out of thirty that common stock price exceeded conversion price		20
Number of consecutive trading days in period		30 days
Holders of notes conversion percentage of conversion price		130.00%
Notes trading price percentage		98.00%
Debt issuance cost		$ 6,400,000
Debt issuance costs attributable to the equity component		1,700,000
Deferred tax assets, net		$ 600,000
Debt | Designated as Hedging Instrument
Schedule of Convertible Senior Notes
Note hedge, aggregate amount	$ 63,500,000