Lease - Other lease information (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Leases
Operating cash flows from operating leases	$ 41,703
Operating cash flows from finance leases	765
Financing cash flows from finance leases	2,927
Right-of-use assets obtained in exchange for lease obligations, operating leases	$ 44,125
Right-of-use assets obtained in exchange for lease obligations, finance leases		$ 7,382
Weighted-average remaining lease term (years), operating leases	5 years 3 months 14 days
Weighted-average remaining lease term (years), finance leases	5 years 6 months 21 days
Weighted-average discount rate, operating leases	4.21%
Weighted-average discount rate, finance leases	8.49%
Minimum
Leases
Lease terms	1 year
Maximum
Leases
Lease terms	5 years