Financial Instruments - Fair Value Assets and Liabilities Measured on Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Recurring
Restricted investments:
Rabbi Trust	$ 36,982	$ 42,937
Marketable equity and fixed income securities	25,939	11,551
Fixed income securities		1,927
Recurring | Significant Other Observable Inputs (Level 2)
Restricted investments:
Rabbi Trust	36,982	42,937
Marketable equity and fixed income securities	25,939	11,551
Fixed income securities		1,927
Interest Rate Swap
Restricted investments:
Interest rate swap derivatives	4,600
Interest Rate Swap | Recurring
Restricted investments:
Interest rate swap derivatives	4,613
Liabilities:
Interest rate swap derivatives		3,195
Interest Rate Swap | Recurring | Significant Other Observable Inputs (Level 2)
Restricted investments:
Interest rate swap derivatives	$ 4,613
Liabilities:
Interest rate swap derivatives		$ 3,195