Debt - Additional Information (Details)			1 Months Ended	12 Months Ended
	Oct. 18, 2017 USD ($)	Aug. 17, 2017 USD ($)	May 31, 2013 USD ($) day $ / shares shares	Dec. 31, 2017 USD ($) shares	Dec. 31, 2016 USD ($) shares	Dec. 31, 2015 USD ($) shares
Debt Instrument [Line Items]
Deferred tax assets, net				$ 2,635,000
Common stock repurchased and retired (in shares) | shares			600,000	2,325,825	2,524,752	4,907,675
Share repurchases			$ 30,000,000	$ 110,000,000	$ 112,488,000	$ 215,911,000
Strike price of warrants | $ / shares			$ 83.18
Proceeds from issuance of warrants			$ 43,600,000
Designated as hedging instrument
Debt Instrument [Line Items]
Note hedge, aggregate amount			63,500,000
Line of Credit
Debt Instrument [Line Items]
Origination costs				$ 5,600,000
Line of Credit | Revolving Credit Facility
Debt Instrument [Line Items]
Repricing premium		1.00%
Term of debt instrument				5 years
Remaining undrawn loan amount	$ 200,000,000
Maximum borrowing capacity		$ 200,000,000
Line of Credit | Revolving Credit Facility | LIBOR
Debt Instrument [Line Items]
Basis spread		1.75%
Line of Credit | Revolving Credit Facility | LIBOR | Minimum
Debt Instrument [Line Items]
Basis spread		1.50%
Line of Credit | Revolving Credit Facility | LIBOR | Maximum
Debt Instrument [Line Items]
Basis spread		1.75%
Line of Credit | Revolving Credit Facility | Base Rate
Debt Instrument [Line Items]
Basis spread		0.75%
Line of Credit | Revolving Credit Facility | Base Rate | Minimum
Debt Instrument [Line Items]
Basis spread		0.50%
Line of Credit | Revolving Credit Facility | Base Rate | Maximum
Debt Instrument [Line Items]
Basis spread		0.75%
Term Loan
Debt Instrument [Line Items]
Amortization rate percentage		0.25%
Term of debt instrument				7 years
Amount drawn on the loan facility	$ 300,000,000
Maximum borrowing capacity		$ 300,000,000
Amount of issuance of debt				$ 300,000,000
Debt issuance costs				4,543,000
Term Loan | LIBOR
Debt Instrument [Line Items]
Basis spread	2.50%
Term Loan | Credit Agreement, LIBOR Rate Option | LIBOR
Debt Instrument [Line Items]
Interest rate floor	0.00%	0.00%
Term Loan | Credit Agreement, Base Rate Option | LIBOR
Debt Instrument [Line Items]
Basis spread		1.00%
Term Loan | Credit Agreement, Base Rate Option | Federal Funds Effective Swap Rate
Debt Instrument [Line Items]
Basis spread		0.50%
Convertible Senior Notes
Debt Instrument [Line Items]
Origination costs			6,400,000
Amount of issuance of debt			$ 300,000,000.0	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 | $ / shares			$ 64.17
Convertible debt, conversion threshold | day			20
Number of consecutive trading days in period | day			30
Holders of notes conversion percentage of conversion price			130.00%
Notes trading price percentage			98.00%
Debt issuance costs				5,946,000	$ 21,208,000
Issuance costs attributable to the equity component of convertible debt			$ 1,700,000
Debt issuance cost, attributable to liability component				$ 500,000
Deferred tax assets, net			$ 600,000