Leases - Components of Lease Expense (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Finance lease cost:
Amortization of leased assets	$ 4,043	$ 4,245
Interest on lease liabilities	2,695	2,169
Sublease income	(2,087)	(2,087)
Total	19,716	19,776
Property operating expenses
Operating lease cost:
Lease expense	12,516	14,679
General and administrative expenses
Operating lease cost:
Lease expense	$ 2,549	$ 770