Supplemental Executive Retirement Plans - Plan details and change in benefit obligation (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022 USD ($)	Jun. 30, 2021 USD ($)	Jun. 30, 2022 USD ($) payment	Jun. 30, 2021 USD ($)	Dec. 31, 2021 USD ($)
Retirement Benefits [Abstract]
Number of annual payments | payment			15
Change in Benefit Obligation
Benefit obligation at the beginning of the period	$ 16,273	$ 18,079	$ 17,935	$ 19,746
Service cost	116	123	232	246
Interest cost	100	88	199	175
Payments	(12)	(12)	(1,889)	(1,889)
Benefit obligation at the end of the period	16,477	$ 18,278	16,477	$ 18,278
Amounts Recognized in the Condensed Consolidated Balance Sheets:
Current accrued expenses and other current liabilities	1,913		1,913		$ 1,913
Non-current other liabilities	14,564		14,564		16,022
Total accrued liabilities	$ 16,477		$ 16,477		$ 17,935