Interest Rate Swaps - Impact of Interest Rate Swaps on Consolidated Statements of Operations - (Detail) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Sep. 30, 2018	Jun. 30, 2020	Jun. 30, 2019
Derivative [Line Items]
Total interest expense presented in the Consolidated Statement of Operations in which the effects of cash flow hedges are recorded (line item “Interest expense”)	$ 7,428	$ 6,255		$ 14,877	$ 12,726
Increase in interest expense	8,300			8,300
Interest Rate Swap
Derivative [Line Items]
Total interest expense presented in the Consolidated Statement of Operations in which the effects of cash flow hedges are recorded (line item “Interest expense”)	7,428		$ 6,255	14,877	12,726
Interest Rate Swap | Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent
Derivative [Line Items]
Amount of loss recognized in AOCI on derivatives	(1,920)		(7,761)	(17,318)	(12,036)
Reclassification out of Accumulated Other Comprehensive Income | Interest Rate Swap | Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent
Derivative [Line Items]
Amount of (loss) gain reclassified from AOCI into earnings under “Interest expense”	$ (1,694)		$ 788	$ (2,124)	$ 1,640