Other Investments (Schedule of Unrealized Gains and Losses Related to Equity Securities) (Detail) - USD ($) $ in Thousands	6 Months Ended
Sep. 30, 2019	Sep. 30, 2018
Other Investments [Abstract]
Net gains and losses recognized during the period on equity securities	$ (2,435)
Less: Net gains and losses recognized during the period on equity securities sold during the period	0	$ 0
Unrealized gains and losses recognized during the reporting period on equity securities still held at the reporting date	$ (2,435)

Amount of realized gain (loss) from sale of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 321
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=116654751&loc=SL75117546-209714

Name:	us-gaap_EquitySecuritiesFvNiRealizedGainLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration