Benefit plans - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, matching amount		$ 690,000	$ 432,000
Regular Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, matching percentage		1.75%
Net periodic benefit cost		$ 249,000	268,000
Projected benefit obligation		1,000,000.0	897,000
Projected benefit obligation, plan assets		886,000	636,000
Net pension liability		116,000	261,000
Actuarial gain (loss)		127,000	(84,000)
Estimates future benefit payments from 2022 to 2026		411,000
Estimates future benefit payments, 2027 and thereafter		538,000
Regular Pension Plan [Member] | Forecast [Member]
Defined Benefit Plan Disclosure [Line Items]
Company contributions	$ 272,000
Top Hat Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan legal yield guarantee percent				1.75%
Net periodic benefit cost		389,000	916,000
Projected benefit obligation		1,700,000	1,700,000
Projected benefit obligation, plan assets		1,200,000	629,000
Net pension liability		463,000	1,100,000
Actuarial gain (loss)		472,000	$ (52,000)
Estimates future benefit payments from 2022 to 2026		79,000
Estimates future benefit payments, 2027 and thereafter		$ 281,000
Top Hat Plan [Member] | Forecast [Member]
Defined Benefit Plan Disclosure [Line Items]
Company contributions	$ 382,000