Leases - Costs and Supplemental Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Operating lease expense	$ 18,481	$ 18,852
Variable lease expense	2,830	2,924
Sublease income	(749)	(791)
Total lease expense	20,562	20,985
ROU assets	84,227	102,779
Lease liabilities	$ 96,812	$ 109,608
Weighted average remaining lease term	7 years 6 months	8 years 1 month 6 days
Weighted average discount rate	2.96%	3.05%
Cash paid for amounts included in the measurement of lease liabilities	$ 18,973	$ 18,563
ROU assets obtained in exchange for lease obligations	$ 2,931	$ 117,496
Operating Lease, Liability, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilities	us-gaap:OtherLiabilities