Lease - Components of lease costs (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Components of operating lease costs
Operating lease cost	$ 10,630	$ 10,531
Less operating lease and sublease income	(618)	(388)
Net operating lease cost	10,012	10,143
Amortization of ROU assets	147	147
Interest on lease liabilities	144	152
Total finance lease cost	$ 291	$ 299