Stock Based Compensation - Schedule of Changes in Stock Units (Detail) - $ / shares	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Balance at beginning of period	46,598	95,888
Grants	15,425	12,110
Vesting	(23,898)	(31,081)
Forfeited/expired	(200)	(1,027)
Balance at end of period	37,925	75,890
Balance at beginning of period	$ 35.75	$ 29.89
Weighted Average Grant Date Fair Value, Grants	40.89	49.58
Weighted Average Grant Date Fair Value, Vesting	40.40	28.42
Weighted Average Grant Date Fair Value, Forfeited/expired	29.70	34.55
Balance at end of period	$ 34.94	$ 33.57
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Balance at beginning of period	22,597
Grants	0
Vesting	0
Forfeited/expired	0
Balance at end of period	22,597
Balance at beginning of period	$ 48.91
Weighted Average Grant Date Fair Value, Grants	0
Weighted Average Grant Date Fair Value, Vesting	0
Weighted Average Grant Date Fair Value, Forfeited/expired	0
Balance at end of period	$ 48.91
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Balance at beginning of period	22,597
Grants	0
Vesting	0
Forfeited/expired	0
Balance at end of period	22,597
Balance at beginning of period	$ 48.91
Weighted Average Grant Date Fair Value, Grants	0
Weighted Average Grant Date Fair Value, Vesting	0
Weighted Average Grant Date Fair Value, Forfeited/expired	0
Balance at end of period	$ 48.91