Pension Plan and Employee Benefits - Fair Value of Pension Plan Assets (Details) - PENSION BENEFITS - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Total net assets	$ 527,427	$ 516,120	$ 460,097
Cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Total net assets	7,433	19,567
Government securities
Defined Benefit Plan Disclosure [Line Items]
Total net assets	75,815	26,863
Mutual funds, Domestic
Defined Benefit Plan Disclosure [Line Items]
Total net assets	106,694	107,055
Mutual funds, International
Defined Benefit Plan Disclosure [Line Items]
Total net assets	56,169	60,104
Real estate funds
Defined Benefit Plan Disclosure [Line Items]
Total net assets	39,091	35,962
Corporate debt
Defined Benefit Plan Disclosure [Line Items]
Total net assets	166,435	192,261
Interest accrual
Defined Benefit Plan Disclosure [Line Items]
Total net assets	2,019	2,264
Defined Benefit Plan, Common Collective Trust
Defined Benefit Plan Disclosure [Line Items]
Total net assets	$ 73,771	$ 72,044
Defined Benefit Plan, Plan Assets, Fair Value by Hierarchy and NAV [Extensible Enumeration]	Fair Value Measured at Net Asset Value Per Share [Member]	Fair Value Measured at Net Asset Value Per Share [Member]
Fair Value, Inputs, Level 1, 2 and 3
Defined Benefit Plan Disclosure [Line Items]
Total net assets	$ 451,637	$ 441,812
QUOTED PRICES IN ACTIVE MARKETS FOR IDENTICAL ASSETS (LEVEL 1)
Defined Benefit Plan Disclosure [Line Items]
Total net assets	162,863	167,159
QUOTED PRICES IN ACTIVE MARKETS FOR IDENTICAL ASSETS (LEVEL 1) | Cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Total net assets	0	0
QUOTED PRICES IN ACTIVE MARKETS FOR IDENTICAL ASSETS (LEVEL 1) | Government securities
Defined Benefit Plan Disclosure [Line Items]
Total net assets	0	0
QUOTED PRICES IN ACTIVE MARKETS FOR IDENTICAL ASSETS (LEVEL 1) | Mutual funds, Domestic
Defined Benefit Plan Disclosure [Line Items]
Total net assets	106,694	107,055
QUOTED PRICES IN ACTIVE MARKETS FOR IDENTICAL ASSETS (LEVEL 1) | Mutual funds, International
Defined Benefit Plan Disclosure [Line Items]
Total net assets	56,169	60,104
QUOTED PRICES IN ACTIVE MARKETS FOR IDENTICAL ASSETS (LEVEL 1) | Real estate funds
Defined Benefit Plan Disclosure [Line Items]
Total net assets	0	0
QUOTED PRICES IN ACTIVE MARKETS FOR IDENTICAL ASSETS (LEVEL 1) | Corporate debt
Defined Benefit Plan Disclosure [Line Items]
Total net assets	0	0
SIGNIFICANT OTHER OBSERVABLE INPUTS (LEVEL 2)
Defined Benefit Plan Disclosure [Line Items]
Total net assets	249,683	238,691
SIGNIFICANT OTHER OBSERVABLE INPUTS (LEVEL 2) | Cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Total net assets	7,433	19,567
SIGNIFICANT OTHER OBSERVABLE INPUTS (LEVEL 2) | Government securities
Defined Benefit Plan Disclosure [Line Items]
Total net assets	75,815	26,863
SIGNIFICANT OTHER OBSERVABLE INPUTS (LEVEL 2) | Mutual funds, Domestic
Defined Benefit Plan Disclosure [Line Items]
Total net assets	0	0
SIGNIFICANT OTHER OBSERVABLE INPUTS (LEVEL 2) | Mutual funds, International
Defined Benefit Plan Disclosure [Line Items]
Total net assets	0	0
SIGNIFICANT OTHER OBSERVABLE INPUTS (LEVEL 2) | Real estate funds
Defined Benefit Plan Disclosure [Line Items]
Total net assets	0	0
SIGNIFICANT OTHER OBSERVABLE INPUTS (LEVEL 2) | Corporate debt
Defined Benefit Plan Disclosure [Line Items]
Total net assets	166,435	192,261
SIGNIFICANT UNOBSERVABLE INPUTS (LEVEL 3)
Defined Benefit Plan Disclosure [Line Items]
Total net assets	39,091	35,962
SIGNIFICANT UNOBSERVABLE INPUTS (LEVEL 3) | Cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Total net assets	0	0
SIGNIFICANT UNOBSERVABLE INPUTS (LEVEL 3) | Government securities
Defined Benefit Plan Disclosure [Line Items]
Total net assets	0	0
SIGNIFICANT UNOBSERVABLE INPUTS (LEVEL 3) | Mutual funds, Domestic
Defined Benefit Plan Disclosure [Line Items]
Total net assets	0	0
SIGNIFICANT UNOBSERVABLE INPUTS (LEVEL 3) | Mutual funds, International
Defined Benefit Plan Disclosure [Line Items]
Total net assets	0	0
SIGNIFICANT UNOBSERVABLE INPUTS (LEVEL 3) | Real estate funds
Defined Benefit Plan Disclosure [Line Items]
Total net assets	39,091	35,962	$ 18,017
SIGNIFICANT UNOBSERVABLE INPUTS (LEVEL 3) | Corporate debt
Defined Benefit Plan Disclosure [Line Items]
Total net assets	$ 0	$ 0