Revenue Recognition - Components of Lease Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Revenue from Contract with Customer [Abstract]
Fixed lease revenues	$ 33,590	$ 35,903	$ 67,739	$ 71,632
Variable lease revenues	10,509	17,931	28,346	36,698
Lease revenues	$ 44,099	$ 53,834	$ 96,085	$ 108,330