Recent Accounting Standards - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Jan. 01, 2018	Dec. 31, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Change in tax rate, deferred tax asset, provisional income tax expense	$ 1,700
Transition tax for accumulated foreign earnings, provisional liability	12,000
Increase to retained earnings	684,540		$ 591,349
Accounting Standards Update 2016-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred tax asset, adjustment			$ 12,700
Forecast
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increase to retained earnings		$ 4,000
Interest rate swap | Accounting Standards Update 2017-12
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect on retained earnings	$ 200