Leases - Supplemental cash flow information related to leases (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Related Party Transaction [Line Items]
Operating cash flow for operating leases	$ 7,726	$ 9,131
Investing cash flow for operating leases	3,423	876
Operating cash flow for finance leases	19	19
Financing cash flow for finance leases	304	282
Subsidiaries
Related Party Transaction [Line Items]
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	4,996	1,840
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	$ 4,996	$ 1,840