Income Taxes (Narrative) (Details) - USD ($)	3 Months Ended		6 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Income Taxes [Abstract]
Income tax benefit	$ 13,620,000	$ 6,783,000	$ 15,804,000	$ 11,584,000
Effective income tax rate	12.70%	26.70%	10.70%	24.30%
Tax receivable agreement, percentage of net cash saving realized assigned			85.00%
Tax receivable agreement, minimum percentage of the Joint Venture outstanding units required to be owned			20.00%
Additional tax receivable agreement, percentage net cash tax savings Company required to pay arising from certain tax basis increases and imputed interest deductions			85.00%
Net cash tax savings, obligation	$ 0		$ 0
Letter agreement, percentage of tax savings required to pay if amount of deductions allocated to Company are in excess of specified minimum threshold			100.00%
Due to McKesson	$ 48,363,000		$ 48,363,000