Debt - 2.5% Convertible Notes (Details)		3 Months Ended
	Feb. 14, 2014 USD ($)	Mar. 31, 2017 USD ($) day $ / shares	Dec. 31, 2016 USD ($)	Feb. 28, 2014 USD ($)
Debt Instrument [Line Items]
Carrying value of convertible debt		$ 181,566,000	$ 179,363,000
Convertible 2.5% notes
Debt Instrument [Line Items]
Aggregate principal amount of debt issued				$ 200,000,000
Net proceeds from issuance of convertible debt	$ 193,300,000
Fees and expenses	6,700,000
Proceeds used to pay the cost of the bond hedges	$ 14,100,000
Interest rate (as a percent)	2.50%
Initial conversion rate of common stock per $1000 of principal amount		0.0369079
Initial conversion price of convertible notes into common stock (in usd per share) | $ / shares		$ 27.09
Consecutive trading period (in days)		30 days
Principal amount used for debt instrument conversion ratio		$ 1,000
Period of amortization of debt discount to interest expense using effective interest method (in years)		5 years
Debt issuance costs allocated to equity component	$ 1,300,000
Debt issuance costs allocated to the liability component	5,400,000
Debt term (in years)		5 years
Effective interest rate on liability component (as a percent)		7.23%
Principal amount of debt outstanding		$ 199,998,000
Carrying value of convertible debt		$ 181,566,000
Convertible 2.5% notes | Debt Instrument Convertible Covenant One
Debt Instrument [Line Items]
Trading period (in days) | day		20
Consecutive trading period (in days)		30 days
Convertible 2.5% notes | Debt Instrument Convertible Covenant One | Minimum
Debt Instrument [Line Items]
Closing sales price of the entity's common stock that the conversion price must exceed or be equal in order for the notes to be convertible (as a percent)		130.00%
Convertible 2.5% notes | Debt Instrument Convertible Covenant Two
Debt Instrument [Line Items]
Consecutive business days after any five consecutive trading day period during the note measurement period (in days)		5 days
Consecutive trading days before five consecutive business days during the note measurement period (in days)		5 days
Principal amount used for debt instrument conversion ratio		$ 1,000
Convertible 2.5% notes | Debt Instrument Convertible Covenant Two | Maximum
Debt Instrument [Line Items]
Product of the last reported sale price of the entity's common stock and the conversion rate of convertible debt instruments (less than) (as a percent)		98.00%
Convertible 2.5% notes, net
Debt Instrument [Line Items]
Aggregate principal amount of debt issued	$ 200,000,000	$ 200,000,000.0
Interest rate (as a percent)		2.50%	2.50%
Convertible 2.5% notes, net | Convertible 2.5% notes
Debt Instrument [Line Items]
Period of amortization of debt discount to interest expense using effective interest method (in years)	5 years
Principal amount of debt outstanding		$ 200,000,000
Carrying value of convertible debt		$ 181,600,000