New Accounting Pronouncements - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jan. 01, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Income tax benefit, excess tax deductions for stock-based compensation		$ 6,300
Deferred tax assets, stock-based compensation expense	$ 8,998	15,038
Deferred tax assets valuation allowance	89,508	113,699
Net cash provided by operating activities	352,794	477,812	$ 407,960
Net cash provided by (used in) financing activities	$ 1,272,130	(207,040)	(339,930)
ASU 2016-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred tax assets, stock-based compensation expense				$ 15,400
Deferred tax assets valuation allowance				$ 15,400
Net cash provided by operating activities			6,900
Net cash provided by (used in) financing activities			(6,900)
ASU 2016-05
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net cash provided by operating activities		18,000
Net cash provided by (used in) financing activities		(18,000)
ASU 2016-18
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net cash provided by operating activities		$ 700	$ (3,800)