Benefit Plans - Fair Value Measurement of Plan Assets (Details) - Pension Plan - USD ($)	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Benefit Plans
Fair value of plan assets	$ 77,603,000	$ 78,149,000	$ 106,648,000
Percentage of total	100.00%	100.00%
Cash and cash equivalents
Benefit Plans
Fair value of plan assets	$ 2,353,000	$ 1,712,000
Fixed income securities
Benefit Plans
Percentage of total	86.40%	86.90%
U.S. Treasury securities
Benefit Plans
Fair value of plan assets	$ 11,354,000	$ 6,593,000
US Government Agencies Debt Securities [Member]
Benefit Plans
Fair value of plan assets	5,899,000	6,656,000
Fixed income - U.S. corporate securities
Benefit Plans
Fair value of plan assets	47,546,000	53,051,000
Fixed income - municipal securities
Benefit Plans
Fair value of plan assets	379,000	382,000
Fixed income - international securities
Benefit Plans
Fair value of plan assets	1,901,000	1,199,000
Equity - large-cap exchange-traded fund
Benefit Plans
Fair value of plan assets	5,311,000	5,544,000
Equity - mid-cap exchange-traded funds
Benefit Plans
Fair value of plan assets	844,000	1,001,000
Equity - small-cap exchange-traded funds
Benefit Plans
Fair value of plan assets	394,000	461,000
Equity - international funds
Benefit Plans
Fair value of plan assets	1,622,000	1,550,000
Fair Value, Inputs, Level 1 [Member]
Benefit Plans
Fair value of plan assets	12,425,000	11,467,000
Fair Value, Inputs, Level 1 [Member] | Cash and cash equivalents
Benefit Plans
Fair value of plan assets	2,353,000	1,712,000
Fair Value, Inputs, Level 1 [Member] | Fixed income - international securities
Benefit Plans
Fair value of plan assets	1,901,000	1,199,000
Fair Value, Inputs, Level 1 [Member] | Equity - large-cap exchange-traded fund
Benefit Plans
Fair value of plan assets	5,311,000	5,544,000
Fair Value, Inputs, Level 1 [Member] | Equity - mid-cap exchange-traded funds
Benefit Plans
Fair value of plan assets	844,000	1,001,000
Fair Value, Inputs, Level 1 [Member] | Equity - small-cap exchange-traded funds
Benefit Plans
Fair value of plan assets	394,000	461,000
Fair Value, Inputs, Level 1 [Member] | Equity - international funds
Benefit Plans
Fair value of plan assets	1,622,000	1,550,000
Fair Value, Inputs, Level 2 [Member]
Benefit Plans
Fair value of plan assets	65,178,000	66,682,000
Fair Value, Inputs, Level 2 [Member] | U.S. Treasury securities
Benefit Plans
Fair value of plan assets	11,354,000	6,593,000
Fair Value, Inputs, Level 2 [Member] | US Government Agencies Debt Securities [Member]
Benefit Plans
Fair value of plan assets	5,899,000	6,656,000
Fair Value, Inputs, Level 2 [Member] | Fixed income - U.S. corporate securities
Benefit Plans
Fair value of plan assets	47,546,000	53,051,000
Fair Value, Inputs, Level 2 [Member] | Fixed income - municipal securities
Benefit Plans
Fair value of plan assets	379,000	382,000
Fair Value, Inputs, Level 3 [Member]
Benefit Plans
Fair value of plan assets	$ 0	$ 0