Summary of Fair Value of Plan Assets by Asset Category (Details) - USD ($) $ in Thousands	Dec. 31, 2021		Dec. 31, 2020		Dec. 31, 2019
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets	$ 44,187		$ 45,689		$ 38,983
Estimate of Fair Value Measurement | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets	163		866
Not Subject to Leveling
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets	44,024		44,823
Balanced Fund
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets	30,774	[1]	31,572	[2]
Balanced Fund | Not Subject to Leveling
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets	30,774	[1]	31,572	[2]
Fixed Income
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets	13,250	[3]	13,251	[4]
Fixed Income | Not Subject to Leveling
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets	13,250	[3]	13,251	[4]
Cash
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets	163		866
Cash | Estimate of Fair Value Measurement | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets	$ 163		$ 866

[1] This class comprises a diversified portfolio of global investments which seeks a balanced return between capital growth and fixed income and is allocated on a weighted average basis as follows: equities (35%), bonds (39%), other assets (21%) and cash (5%).

[2] This class comprises a diversified portfolio of global investments which seeks a balanced return between capital growth and fixed income and is allocated on a weighted average basis as follows: equities (35%), bonds (37%), other assets (19%) and cash (9%).

[3] This class comprises a diversified portfolio of global investments which seeks fixed income growth and is allocated on a weighted average basis as follows: bonds (88%), other assets (6%), and cash (6)%.

[4] This class comprises a diversified portfolio of global investments which seeks fixed income growth and is allocated on a weighted average basis as follows: bonds (83%), other assets (16%) and cash (1%).