Intangible Assets - Intangible Assets, Other than Capitalized Software Development Costs (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Mar. 31, 2020
Finite Lived Intangible Assets [Line Items]
Gross carrying amount	$ 153,150	$ 153,150
Accumulated amortization	(101,589)	(95,341)
Net intangible assets	51,561	57,809
Customer Relationships
Finite Lived Intangible Assets [Line Items]
Gross carrying amount	39,200	39,200
Accumulated amortization	(23,051)	(21,951)
Net intangible assets	16,149	17,249
Trade Names
Finite Lived Intangible Assets [Line Items]
Gross carrying amount	250	250
Accumulated amortization	(29)	(17)
Net intangible assets	221	233
Computer Software, Intangible Asset
Finite Lived Intangible Assets [Line Items]
Gross carrying amount	113,700	113,700
Accumulated amortization	(78,509)	(73,373)
Net intangible assets	$ 35,191	$ 40,327