Leases - Supplemental balance sheet information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Lease liabilities	$ 108,743	$ 122,221
Cash paid for amounts included in the measurement of lease liabilities within operating cash flows	28,276	26,458
Right of use assets obtained in exchange for operating lease obligations	$ 8,904	$ 37,673
Weighted average remaining lease term	6 years 8 months 12 days	7 years 2 months 12 days
Weighted average discount rate	4.00%	4.40%