Derivatives - Effect on Statements of Operations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Interest expense presented in the Statements of Operations in which the effects of cash flow hedges are recorded	$ 76,571	$ 73,746	$ 146,092
Interest rate swaps | Cash flow hedges
Derivative Instruments, Gain (Loss) [Line Items]
Amount of loss recognized in other comprehensive income on derivative	11,080	1,567
Amount of loss (gain) reclassified from AOCI into income	314	(1,041)
Interest expense presented in the Statements of Operations in which the effects of cash flow hedges are recorded	76,571	$ 73,746
Derivative, Credit Risk Related Contingent Features [Abstract]
Termination value of derivatives in a liability position	12,818
Termination value of derivative agreements	$ 12,818