Accumulated Other Comprehensive Income (Loss) - Summary of Changes in Accumulated Other Comprehensive Income (Loss) (Parenthetical) (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014
Equity [Abstract]
Other comprehensive income (loss) before reclassifications, tax benefit	$ 2,354
Tax expense (benefit) associated with change in pension actuarial loss	(446)
Amounts reclassified out of accumulated other comprehensive income (loss), tax expense	$ 4,123