Indebtedness - Schedule of Indebtedness (Parenthetical) (Detail)	6 Months Ended
	Jun. 30, 2014
Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Debt instrument, Maturity	2014
Unsecured Bank Term Loan [Member]
Debt Instrument [Line Items]
Effective blended interest rate	3.24%
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