Pension and Other Postretirement Benefits - Summary (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 117	$ 120	$ 352	$ 359
Interest expense	1,029	1,155	3,088	3,464
Expected return on plan assets	(1,121)	(1,286)	(3,363)	(3,858)
Amortization of prior service cost	10	11	31	32
Settlement loss	271	91	819	609
Actuarial loss	456	422	1,368	1,267
Net periodic pension cost	762	513	2,295	1,873
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	2	4	5	11
Interest expense	82	83	246	248
Amortization of prior service cost	(177)	(177)	(531)	(532)
Actuarial loss	109	109	328	328
Net periodic pension cost	$ 16	$ 19	$ 48	$ 55