Accumulated Other Comprehensive Income - Schedule of Changes in Accumulated Other Comprehensive Income by Component Net of Tax (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
Accumulated Other Comprehensive Income (Loss) [Line Items]
Unrealized holding gain (loss) on available-for-sale securities arising during the period, Pretax	$ 584	$ (3,326)	$ 1,356	$ (4,072)
Reclassify gain included in income, Pretax	(133)	(10)	(133)	(10)
Unrealized holding gain (loss) on available-for-sale securities arising during the period, Tax (Expense) Benefit	153	(1,134)	416	(1,388)
Reclassify gain included in income, Tax (Expense) Benefit	18		35
Beginning balance, After-tax			(1,456)
Ending balance, After-tax	(580)		(580)
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance, Pretax	(1,381)	2,079	(2,207)	2,824
Unrealized holding gain (loss) on available-for-sale securities arising during the period, Pretax	584	(3,327)	1,356	(4,072)
Reclassify gain included in income, Pretax	(133)	(10)	(133)	(10)
Amortization of held-to-maturity discount resulting from transfer, Pretax	52		104
Total other comprehensive loss, Pretax	503	(3,337)	1,327	(4,082)
Ending balance, Pretax	(878)	(1,258)	(878)	(1,258)
Beginning balance, Tax (Expense) Benefit	469	(707)	751	(960)
Unrealized holding gain (loss) on available-for-sale securities arising during the period, Tax (Expense) Benefit	(198)	1,132	(461)	1,385
Reclassify gain included in income, Tax (Expense) Benefit	45	3	45	3
Amortization of held-to-maturity discount resulting from transfer, Tax (Expense) Benefit	(18)		(35)
Total other comprehensive loss, Tax (Expense) Benefit	(171)	1,135	(451)	1,388
Ending balance, Tax (Expense) Benefit	298	428	298	428
Beginning balance, After-tax	(912)	1,372	(1,456)	1,864
Unrealized holding gain (loss) on available-for-sale securities arising during the period, After-tax	386	(2,195)	895	(2,687)
Reclassify gain included in income, After-tax	(88)	(7)	(88)	(7)
Amortization of held-to-maturity discount resulting from transfer, After-tax	34		69
Total other comprehensive loss, After-tax	332	(2,202)	876	(2,694)
Ending balance, After-tax	$ (580)	$ (830)	$ (580)	$ (830)