Intangible Assets - Intangible Assets, Other than Capitalized Software Development Costs (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Mar. 31, 2019
Finite Lived Intangible Assets [Line Items]
Gross carrying amount	$ 125,400	$ 148,760
Accumulated amortization	(83,110)	(96,165)
Net intangible assets	42,290	52,595
Customer Relationships
Finite Lived Intangible Assets [Line Items]
Gross carrying amount	32,400	54,450
Accumulated amortization	(19,554)	(39,875)
Net intangible assets	12,846	14,575
Computer Software, Intangible Asset
Finite Lived Intangible Assets [Line Items]
Gross carrying amount	93,000	94,310
Accumulated amortization	(63,556)	(56,290)
Net intangible assets	$ 29,444	$ 38,020