Derivative Instruments and Hedging Activities - Amounts Included in Accumulated Other Comprehensive (Loss) Income for Derivatives Designated as Hedging Instruments (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Derivative Instruments, Gain (Loss) [Line Items]
Accumulated Other Comprehensive (Loss) Income, fair value, net of taxes	$ (157)	$ 0	$ (1,241)
Interest Rate Swap [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Accumulated Other Comprehensive (Loss) Income, fair value, net of taxes	$ (157)	$ 0	$ (1,241)