Derivatives - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended	9 Months Ended
	Mar. 31, 2016	Sep. 30, 2016	Sep. 30, 2016	Sep. 30, 2015
Derivative Instruments [Line Items]
Repayments of Secured Debt			$ 280,327	$ 272,776
Estimate increase to interest expense		$ 4,000	4,000
Loss on Fair Value Hedge Ineffectiveness	$ 100
Carrying Value Of Net Losses Associated With Interest Rate Swaps		1,700	1,700
Fair value of derivatives in a net liability position		(6,400)	(6,400)
Termination value		$ 7,000	$ 7,000
Interest rate swaps [Member]
Derivative Instruments [Line Items]
Number of derivative, interest rate swap agreement		26	26
Derivative, Weighted average interest rate		1.25%	1.25%
Derivative, notional amount		$ 627,700	$ 627,700
Interest Rate Swap Member Forward Starting [Member]
Derivative Instruments [Line Items]
Number of derivative, interest rate swap agreement		1	1
Derivative, Weighted average interest rate		1.42%	1.42%
Derivative, notional amount		$ 48,000	$ 48,000
Maturity Date		Feb. 01, 2021
Interest Rate Swap Twelve [Member]
Derivative Instruments [Line Items]
Maturity Date			Jan. 02, 2019
Settled Interest Rate Swaps [Member]
Derivative Instruments [Line Items]
Amortization Period of Deferred Gain (Loss) on Discontinuation of Fair Value Hedge			10 years