Pension and Other Postretirement Benefits - Plan Asset Redemptions (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 90,421	$ 96,147	$ 100,765
U.S. Plans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	28,348	32,568	$ 37,659
Diversified funds | U.S. Plans | Fair Value Measured at Net Asset Value Per Share
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	8
Real estate and other | U.S. Plans | Fair Value Measured at Net Asset Value Per Share
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 4,879	$ 5,482