Effect of Derivative Instruments on Consolidated Statement of Operations (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Designated as Hedging Instrument [Member] | Interest Expense
Derivative Instruments, Gain (Loss) [Line Items]
Loss on Cash Flow Hedge Ineffectiveness	$ (96,000)	$ 44,000	$ 67,000	$ 117,000
Amount of Loss Reclassified from Accumulated OCI into Income (Effective Portion)	(1,042,000)	(1,607,000)	3,359,000	5,590,000
(Loss) Gain on Cash Flow Hedge Ineffectiveness, Net	96,000	(44,000)	(67,000)	(117,000)
Designated as Hedging Instrument [Member] | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (Loss) or Gain Recognized in OCI on Derivative (Effective Portion)	1,179,000	(9,269,000)	(3,840,000)	(11,812,000)
Not Designated as Hedging Instrument [Member] | Interest Expense
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, (Loss) Gain Recognized in Income, Net	$ 0	$ 0	$ 0	$ (3,000)