Leases - Lease Costs (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019	Jun. 30, 2018
Finance lease cost:
Amortization of finance lease right-of-use assets	$ 42	$ 84
Interest expense related to finance lease liabilities	73	143
Operating lease cost	3,339	5,677
Variable lease cost	1,149	1,802
Short-term lease cost	55	110
Total lease cost	4,658	7,816
Cash paid for amounts included in the measurement of lease liabilities
Operating cash outflows for finance lease payments	58	115
Operating cash outflows for operating lease payments	4,084	7,351
Total cash paid for lease liability measurement	4,142	7,466
Right-of-use assets obtained in exchange for new operating lease liabilities	129,511	225,017	$ 0
Right-of-use assets obtained in exchange for new finance lease liabilities	$ 0	$ 8,050
Weighted average remaining lease term - finance leases	47 years 3 months 18 days	47 years 3 months 18 days
Weighted average remaining lease term - operating leases	15 years 10 months 24 days	15 years 10 months 24 days
Weighted average discount rate - operating leases	6.07%	6.07%
Weighted average discount rate - finance leases	3.68%	3.68%