Leases - Supplemental cash flow (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2019 USD ($)
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from finance leases	$ 428
Operating cash flows from operating leases	3,351
Financing cash flows from finance leases	3,723
Total	7,502
Right-of-use assets obtained for new lease obligations:
Operating leases	2,174
Finance leases	2,359
Total	$ 4,533