Indebtedness - Schedule of Indebtedness (Parenthetical) (Detail)	9 Months Ended
	Sep. 30, 2014
Unsecured Bank Term Loan [Member]
Debt Instrument [Line Items]
Debt instrument, Maturity	2018
Effective blended interest rate	3.24%
Secured Mortgage Notes [Member]
Debt Instrument [Line Items]
Debt instrument, Maturity	2019
Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Debt instrument, Maturity	2014
Minimum [Member] | Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Debt instrument, Maturity	2017
Maximum [Member] | Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Debt instrument, Maturity	2022