Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	6 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Mar. 31, 2019	Apr. 01, 2018
Supplemental Cash Flow Information [Abstract]
Cumulative-effect adjustment from adoption of accounting guidance	$ 0	$ 997		$ 997
Shares issued for contingent compensation payment	425	0
Non-cash financing activities:
Dividends declared but not paid	8,023	4,729	$ 5,673
Member distributions declared but not paid	3,836	8,715	$ 17,081
Establishment of net deferred tax assets related to offerings	$ 37,394	$ 37,924