Comprehensive Income - Accumulated Other Comprehensive Income (loss) (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning balance	$ 59,826	$ 50,037	$ 59,237	$ 48,858
Total other comprehensive income (loss)	875	1,236	(2,897)	2,840
Ending balance	61,560	52,655	61,560	52,655
Unrealized Holding Gains on Available-for-Sale Securities (Net) [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning balance	388	1,927	4,160	323
Other comprehensive income (loss) before reclassifications, net of ($275), ($370), $662 and ($860) tax effect, respectively	912	1,236	(2,110)	2,887
Amounts reclassified from accumulated other comprehensive income, net of $14, $0, $204 and $11 tax effect, respectively	(37)		(787)	(47)
Total other comprehensive income (loss)	875	1,236	(2,897)	2,840
Ending balance	$ 1,263	$ 3,163	$ 1,263	$ 3,163