Derivative Financial Instruments - Fair Value of Derivative Instruments (Detail) (Derivatives not designated as hedging instruments [Member], USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Other liabilities [Member]
Derivatives, Fair Value [Line Items]
Liability Derivatives	$ 10,080	$ 10,846
Other liabilities [Member] | Interest rate swaps [Member]
Derivatives, Fair Value [Line Items]
Liability Derivatives	10,080	10,846
Other assets [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives	10,080	10,846
Other assets [Member] | Interest rate swaps [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives	$ 10,080	$ 10,846