Leases - Supplemental cash flow information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Leases
Operating cash flows from operating leases	$ 44,814	$ 44,111
Operating cash flows from finance leases	99	28
Financing cash flows from finance leases	556	325
Operating leases	49,380	41,065
Finance leases	2,393	1,245
Right-of-use assets acquired and lease liabilities assumed in acquisitions	$ 5,469	$ 5,189