Pensions and Other Benefits (Details) - USD ($)	Mar. 31, 2020	Mar. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Asset categories:	$ 313,366,000	$ 321,902,000
(Level 1)
Defined Benefit Plan Disclosure [Line Items]
Asset categories:	91,320,000	66,072,000
(Level 2)
Defined Benefit Plan Disclosure [Line Items]
Asset categories:	139,498,000	153,941,000
(Level 3)
Defined Benefit Plan Disclosure [Line Items]
Asset categories:	5,503,000	5,701,000
Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset categories:	77,045,000	96,188,000
Equity securities
Defined Benefit Plan Disclosure [Line Items]
Asset categories:	94,336,000	103,017,000
Equity securities | (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Asset categories:	52,084,000	59,703,000
Equity securities | (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Asset categories:	0	0
Equity securities | (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Asset categories:	0	0
Equity securities | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset categories:	42,252,000	43,314,000
Fixed income
Defined Benefit Plan Disclosure [Line Items]
Asset categories:	199,613,000	205,957,000
Fixed income | (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Asset categories:	24,014,000	602,000
Fixed income | (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Asset categories:	139,498,000	153,941,000
Fixed income | (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Asset categories:	5,503,000	5,701,000
Fixed income | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset categories:	30,598,000	45,713,000
Real Estate Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset categories:	9,401,000	9,978,000
Real Estate Funds [Member] | (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Asset categories:	5,206,000	2,817,000
Real Estate Funds [Member] | (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Asset categories:	0	0
Real Estate Funds [Member] | (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Asset categories:	0	0
Real Estate Funds [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset categories:	4,195,000	7,161,000
Cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Asset categories:	10,016,000	2,950,000
Cash equivalents | (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Asset categories:	10,016,000	2,950,000
Cash equivalents | (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Asset categories:	0	0
Cash equivalents | (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Asset categories:	0	0
Cash equivalents | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset categories:	$ 0	$ 0