Derivatives - AOCI (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Effect of hedge accounting on accumulated other comprehensive loss
Beginning balance			$ (882,647)
Derivative loss reclassified from accumulated other comprehensive loss to interest expense	$ (15)		(15)
Ending balance	(767,435)		(767,435)
Interest expense	(7,332)	$ (11,269)	(17,199)	$ (22,921)
Accumulated Gain (Loss), Cash Flow Hedge
Effect of hedge accounting on accumulated other comprehensive loss
Derivative loss recognized in the current period in accumulated other comprehensive loss	(878)		(878)
Derivative loss reclassified from accumulated other comprehensive loss to interest expense	(15)		(15)
Ending balance	(863)		(863)
Interest Rate Swap
Effect of hedge accounting on accumulated other comprehensive loss
Interest expense	$ (7,332)		$ (17,199)