Derivative Instruments and Hedging Activities - Fair Value of Company's Derivative Financial Instruments Classification on Unaudited Condensed Consolidated Balance Sheets (Detail) - Other Liabilities [Member] - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Derivatives, Fair Value [Line Items]
Liability Derivatives Fair Value	$ 25,011	$ 628
Interest Rate Swaps [Member]
Derivatives, Fair Value [Line Items]
Liability Derivatives Fair Value	2,844	$ 628
Forward Interest Rate Swaps [Member]
Derivatives, Fair Value [Line Items]
Liability Derivatives Fair Value	$ 22,167