Employee Stock Benefit Plans - Summary of Expense Recognized by Share-based Compensation Arrangement (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Employee Stock Benefit Plans
Expense recognized for share-based compensation arrangements	$ 31,175	$ 31,278	$ 41,082
Stock options
Employee Stock Benefit Plans
Expense recognized for share-based compensation arrangements	7,680	12,526	20,478
Time-based Restricted Stock Units
Employee Stock Benefit Plans
Expense recognized for share-based compensation arrangements	18,624	15,488	17,160
Performance-based Restricted Stock Units
Employee Stock Benefit Plans
Expense recognized for share-based compensation arrangements	2,190
Restricted Stock
Employee Stock Benefit Plans
Expense recognized for share-based compensation arrangements	1,886	2,095	2,330
Employee Stock Purchase Plan
Employee Stock Benefit Plans
Expense recognized for share-based compensation arrangements	722	1,115	1,097
Stock awards
Employee Stock Benefit Plans
Expense recognized for share-based compensation arrangements	$ 73	$ 54	$ 17