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	9 Months Ended	12 Months Ended
	Sep. 30, 2013	Dec. 31, 2012
Derivative Instruments Gain Loss Recognized In Other Comprehensive Income Effective Portion Net [Line Items]
Accumulated other comprehensive (loss) income, fair value, net of taxes		$ (1,241)
Interest Rate Swap [Member] | Cash Flow Hedge [Member]
Derivative Instruments Gain Loss Recognized In Other Comprehensive Income Effective Portion Net [Line Items]
Accumulated other comprehensive (loss) income, fair value, net of taxes		$ (1,241)