Summary of Significant Accounting Policies - Schedule of Components of Changes in Accumulated Other Comprehensive Income (Loss) (Parenthetical) (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Accumulated Other Comprehensive Income Loss [Line Items]
Unrealized gain (loss) on derivative instrument, tax expense (benefit)	$ 59	$ (164)	$ 153
Change in Fair Value [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Unrealized gain (loss) on derivative instrument, tax expense (benefit)	59	(164)
Accumulated Other Comprehensive (Loss) Income [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Unrealized gain (loss) on derivative instrument, tax expense (benefit)	$ 59	$ (164)