Investments - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Mar. 31, 2019
Schedule of Equity Method Investments [Line Items]
Equity in income of investees	$ 3,664	$ 5,276	$ 9,877	$ 5,162
Cash received on transfer of other investments			15,750	0
Secured financing	15,913		15,913		$ 0
Amortized cost	14,614		14,614
Net (loss) gain	273		431
Unrealized loss on secured borrowings, fair value adjustment	273		1,136
Proceeds from sales of investments valued under the measurement alternative	6,419		6,419	22,532
Gain on sale of investment	$ 4,973		$ 4,973	$ 11,133
Equity method investments in Partnerships
Schedule of Equity Method Investments [Line Items]
Percent interest in partnerships	1.00%		1.00%

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The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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The net realized gain (loss) on investments sold during the period, not including gains (losses) on securities separately or otherwise categorized as trading, available-for-sale, or held-to-maturity, which, for cash flow reporting, is a component of proceeds from investing activities.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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The net change in the difference between the fair value and the carrying value, or in the comparative fair values, of investments, not including unrealized gains or losses on securities separately or otherwise categorized as trading, available-for-sale, or held-to-maturity, held at each balance sheet date and included in earnings for the period.

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