Leases - Supplemental Cash Flow Information (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019 USD ($)
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows - operating leases	$ 4,657
Financing cash flows - finance leases	43
Finance Lease, Interest Payment on Liability	3
Right-of-use assets obtained in exchange for lease obligations:
Operating leases	3,257
Finance leases	$ 0