Intangible Assets - Intangible Assets, Other than Capitalized Software Development Costs (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Mar. 31, 2020
Finite Lived Intangible Assets [Line Items]
Gross carrying amount	$ 130,950	$ 153,150
Accumulated amortization	(90,829)	(95,341)
Net intangible assets	40,121	57,809
Customer Relationships
Finite Lived Intangible Assets [Line Items]
Gross carrying amount	39,200	39,200
Accumulated amortization	(25,250)	(21,951)
Net intangible assets	13,950	17,249
Trade Names
Finite Lived Intangible Assets [Line Items]
Gross carrying amount	250	250
Accumulated amortization	(55)	(17)
Net intangible assets	195	233
Computer Software, Intangible Asset
Finite Lived Intangible Assets [Line Items]
Gross carrying amount	91,500	113,700
Accumulated amortization	(65,524)	(73,373)
Net intangible assets	$ 25,976	$ 40,327