Fair Value Measurements - Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Mar. 31, 2019
Liabilities:
Liquidating distributions payable	$ 351,876	$ 1,785
Fair Value, Measurements, Recurring [Member]
Assets:
Total Assets	433,190	503,262
Liabilities:
Liquidating distributions payable	351,876	1,785
Fair Value, Measurements, Recurring [Member] | Cash Equivalents [Member] | Money Market Funds [Member]
Assets:
Total Assets	40,413	34
Fair Value, Measurements, Recurring [Member] | Marketable Securities [Member] | U.S. Treasury Bills [Member]
Assets:
Total Assets	392,777	503,228
Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Assets:
Total Assets	40,413	34
Liabilities:
Liquidating distributions payable	351,876	1,785
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Cash Equivalents [Member] | Money Market Funds [Member]
Assets:
Total Assets	40,413	34
Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Assets:
Total Assets	392,777	503,228
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Marketable Securities [Member] | U.S. Treasury Bills [Member]
Assets:
Total Assets	$ 392,777	$ 503,228