Leases - Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$ (8,742)
Operating cash flows from finance leases	(394)
Financing cash flows from finance leases	(4,263)	$ (6,955)
Right-of-use assets obtained in exchange for lease obligations:
Operating leases	1,690
Finance leases	$ 1,295