Debt - Mortgage Loans Payable (Parenthetical) (Detail)							9 Months Ended
	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014 3.00 Loan Due in Aug 2015 [Member]	Sep. 30, 2014 6% Loan Due in Aug 2015 [Member]	Sep. 30, 2014 2.66% Loan Due Oct 2015 [Member]	Sep. 30, 2014 3.50% Loan Due in May 2016 [Member]	Sep. 30, 2014 2.50% Loan Due in May 2016 [Member]	Sep. 30, 2014 2.69% Loan Due in Oct 2016 [Member]
Debt Instrument [Line Items]
LIBOR rate	0.1565%	0.1677%
Debt instrument basis spread on floor rate			0.50%	0.25%		1.00%
Debt instrument interest rate cap basis spread at LIBOR					1.00%
Mortgage loan, LIBOR rate							0.50%	0.69%