Comprehensive Income - Summary of Amounts Recognized in Other Comprehensive Income Loss (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Available-for-sale securities
Realized gain on sale of securities		$ (198)	$ (288)	$ (467)
Impairment expense			193
Available-for-sale securities, Total before tax		(198)	(95)	(467)
Provision for income tax expense		67	32	159
Available-for-sale securities, Net of tax		(131)	(63)	(308)
Defined benefit pension plan items
Amortization of prior service costs	23	26	47	53
Amortization of actuarial gains/(losses)	10	10	20	20
Defined benefit pension plan items, Total before tax	33	36	67	73
Defined benefit pension plan items, Provision for income tax expense	(11)	(12)	(23)	(25)
Defined benefit pension plan items, Net of tax	22	24	44	48
Total reclassifications	$ 22	$ (107)	$ (19)	$ (260)