Stock Based Compensation - Summary of Vested and Unvested Restricted Stock Outstanding (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Balance at beginning of period	95,888	105,309	97,192
Grants	12,110	56,480	67,331
Vesting	(60,011)	(65,662)	(57,406)
Forfeited/expired	(1,389)	(239)	(1,808)
Balance at end of period	46,598	95,888	105,309
Balance at beginning of period	$ 29.89	$ 29.93	$ 25.45
Grants	49.58	29.22	31.80
Vesting	29.25	29.39	31.49
Forfeited/expired	32.76	29.70	27.67
Balance at end of period	$ 35.75	$ 29.89	$ 29.93