Total Taxes on Other Comprehensive Income (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Components of Taxes Other Than Income [Line Items]
(Taxes) benefit on unrealized gains (losses) on securities	$ (156)	$ (34)	$ 46	$ (63)
(Tax) on defined benefit pension plans	6	(2)	1	(5)
Total (taxes) benefit on other comprehensive income (loss)	$ (150)	$ (36)	$ 47	$ (68)