Fair Value Measurements - Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Mar. 31, 2020
Liabilities:
Liquidating distributions payable	$ 57,235	$ 351,876
Fair Value, Measurements, Recurring [Member]
Assets:
Total Assets	119,970	433,190
Liabilities:
Liquidating distributions payable	57,235	351,876
Fair Value, Measurements, Recurring [Member] | Cash equivalents [Member] | Money Market Funds [Member]
Assets:
Total Assets	1,141	40,413
Fair Value, Measurements, Recurring [Member] | Marketable Securities [Member] | U.S. Treasury Bills [Member]
Assets:
Total Assets	118,829	392,777
Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Assets:
Total Assets	1,141	40,413
Liabilities:
Liquidating distributions payable	57,235	351,876
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Cash equivalents [Member] | Money Market Funds [Member]
Assets:
Total Assets	1,141	40,413
Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Assets:
Total Assets	118,829	392,777
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Marketable Securities [Member] | U.S. Treasury Bills [Member]
Assets:
Total Assets	$ 118,829	$ 392,777