Derivatives - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014
Derivative [Line Items]
Variable rate term loan agreement maturity	January 2017
Termination value of derivatives in a net liability position	$ 7,300,000
Collateral obligations for derivative counterparties	18,300,000
Interest Rate Swaps [Member]
Derivative [Line Items]
Notional amount of derivatives	$ 300,000,000