Indebtedness - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended			0 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jan. 29, 2014	Dec. 14, 2011	Jul. 19, 2013	Oct. 31, 2008
Debt Disclosure [Line Items]
Loss from Retirement of Debt	$ (655)	$ (6,637)	$ (9,684)
Unamortized deferred financing cost, wrote off	56
Line of credit facility, maximum borrowing capacity					450,000
Number of years of extension of line of credit facility at election	1 year
Line of credit facility, interest rate description	150
2014 Notes
Debt Disclosure [Line Items]
Extinguishment of Debt, Amount	81,794
Unsecured Credit Facility
Debt Disclosure [Line Items]
Line of credit facility, maximum borrowing capacity						625,000
Line of credit facility, increase, additional borrowings	825,000
Unsecured Debt
Debt Disclosure [Line Items]
Loss from Retirement of Debt		5,003
Unamortized debt issue discount		28
Unamortized deferred financing cost, wrote off		191
Unamortized settlement amount of interest rate protection agreements		1,116
Mortgages
Debt Disclosure [Line Items]
Extinguishment of Debt, Amount	65,558	72,261
Loss from Retirement of Debt	655	1,578
Carrying value of industrial properties held under mortgage	740,281
Unsecured Term Loan
Debt Disclosure [Line Items]
Unsecured Term Loan, Term				7 years
Unsecured Term Loan, Face Amount				200,000
Interest Rate Swap
Debt Disclosure [Line Items]
Swaps, Notional Amount	$ 200,000						$ 50,000