Derivatives (Narrative) (Detail) $ in Thousands		3 Months Ended			5 Months Ended	8 Months Ended	12 Months Ended
	Jul. 28, 2014 USD ($)	Sep. 30, 2016	Mar. 31, 2015 USD ($)	Jun. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2016 USD ($) Agreement	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Derivative Instruments [Line Items]
Estimate increase to interest expense							$ 2,400
Loss recognized in income on derivatives (ineffective portion and amount excluded from effectiveness testing)							(100)	$ (500)	$ (1,800)
Repayment of mortgage loans	$ 25,800						280,327	272,650	76,784
Interest expense, mark to market			$ 500		$ 500
Loss reclassified from Accumulated Other Comprehensive Income (Loss) into income (effective portion)						$ 100	1,500	1,200
Fair value of derivatives in a net liability position							(1,500)
Termination value							(1,500)
Loss on Cash Flow Hedge Ineffectiveness				$ 1,200
Interest Expense [Member]
Derivative Instruments [Line Items]
Loss recognized in income on derivatives (ineffective portion and amount excluded from effectiveness testing)							100	500	1,800
Loss reclassified from Accumulated Other Comprehensive Income (Loss) into income (effective portion)							$ 5,100	$ 5,000	$ 4,300
Interest rate swap [Member]
Derivative Instruments [Line Items]
Number of derivative, interest rate swap agreement | Agreement							26
Derivative, Weighted average interest rate							1.25%
Derivative, notional amount							$ 627,700
Derivative, Maturity Date		Mar. 01, 2021
Period of amortization							10 years
Interest Rate Swap Member Forward Starting [Member]
Derivative Instruments [Line Items]
Number of derivative, interest rate swap agreement							1
Derivative, Weighted average interest rate							1.42%
Derivative, notional amount							$ 48,000
Derivative, Maturity Date		Feb. 01, 2021
Interest Rate Swap Twelve [Member]
Derivative Instruments [Line Items]
Derivative, Maturity Date							Jan. 02, 2019
Interest Rate Swap Eleven and Twelve [Member]
Derivative Instruments [Line Items]
Derivative Liability, Notional Amount, Ineffective							$ 40,000