Reclassification Out of Accumulated Other Comprehensive Income to Statement of Operations (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Unrealized gains	$ 447		$ 702		$ 1,412
Net income	447		702		1,412
Prior service benefit	276	[1]	233	[1]	(14)	[1]
Net income	276		233		(14)
Total reclassifications	$ 723		$ 935		$ 1,398

[1] The amortization of prior service benefit is included in the computation of net periodic pension cost and postretirement benefit; see Note N: "Retirement Plans."