Intangible Assets - Intangible Assets, Other than Capitalized Software Development Costs (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Mar. 31, 2018
Finite Lived Intangible Assets [Line Items]
Gross carrying amount	$ 148,760	$ 148,760
Accumulated amortization	(96,165)	(74,669)
Net intangible assets	52,595	74,091
Customer Relationships
Finite Lived Intangible Assets [Line Items]
Gross carrying amount	54,450	54,450
Accumulated amortization	(39,875)	(35,531)
Net intangible assets	14,575	18,919
Computer Software, Intangible Asset
Finite Lived Intangible Assets [Line Items]
Gross carrying amount	94,310	94,310
Accumulated amortization	(56,290)	(39,138)
Net intangible assets	$ 38,020	$ 55,172