Derivative Instruments and Hedging Activities - Fair Value of Company's Derivative Financial Instruments Classification on Unaudited Condensed Consolidated Balance Sheet (Detail) - Other Liabilities [Member] - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Derivatives, Fair Value [Line Items]
Liability Derivatives Fair Value	$ 8,384	$ 628
Interest Rate Swaps [Member]
Derivatives, Fair Value [Line Items]
Liability Derivatives Fair Value	2,516	$ 628
Forward Interest Rate Swaps [Member]
Derivatives, Fair Value [Line Items]
Liability Derivatives Fair Value	$ 5,868