Stockholders' Equity - Schedule of Reclassification Adjustments (Detail) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Equity [Abstract]
Unrealized gain on investments	$ (72)	$ (45)
Tax effect	27	16
Other Comprehensive Income (Loss), Reclassification Adjustment for Sale of Securities Included in Net Income, Net of Tax	(45)	(29)
Recognized net actuarial loss	827	778
Amortization of prior service credit	(680)	(835)
Tax effect	(56)	(21)
Other comprehensive income loss pension and other postretirement benefit plans, cost reclassification adjustment net of tax, income tax expense	$ 91	$ (78)