Goodwill and Intangible Assets - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 1,581,160	$ 1,581,160
Amortization of intangible assets	$ 22,300	$ 20,900	$ 20,700
Customer relationships and other amortizable intangible assets | Minimum
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible asset, useful life (in years)	3 years
Customer relationships and other amortizable intangible assets | Maximum
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible asset, useful life (in years)	12 years
Software | Minimum
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible asset, useful life (in years)	3 years
Software | Maximum
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible asset, useful life (in years)	5 years