Financial Instruments - Fair Value Assets and Liabilities Measured on Recurring Basis (Details) - Recurring - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Restricted investment:
Rabbi Trust	$ 36,800	$ 42,937
Marketable equity and fixed income securities	16,793	11,551
Fixed income securities		1,927
Significant Other Observable Inputs (Level 2)
Restricted investment:
Rabbi Trust	36,800	42,937
Marketable equity and fixed income securities	16,793	11,551
Fixed income securities		1,927
Interest Rate Swap
Restricted investment:
Interest rate swap derivatives	2,342
Liabilities:
Interest rate swap derivatives		3,195
Interest Rate Swap | Significant Other Observable Inputs (Level 2)
Restricted investment:
Interest rate swap derivatives	$ 2,342
Liabilities:
Interest rate swap derivatives		$ 3,195