Debtor's Condensed Combined Balance Sheets (Detail) - USD ($) $ in Thousands	Jun. 30, 2017	Mar. 31, 2017	Jun. 30, 2016	Mar. 31, 2016
Current assets:
Cash and cash equivalents	$ 683,778	$ 706,404	$ 668,660	$ 678,438
Trade and other receivables, net	116,612	123,262
Marine operating supplies	31,097	30,560
Other current assets	34,619	18,409
Total current assets	1,118,916	1,141,287
Net properties and equipment	2,659,314	2,864,762
Other assets	92,134	139,535
Total assets	3,919,580	4,190,699
Current liabilities:
Accounts payable	35,087	31,599
Accrued expenses	63,155	78,121
Other current liabilities	28,029	48,429
Total current liabilities	260,172	2,328,713
Other liabilities and deferred credits	60,382	154,705
Liabilities subject to compromise	2,389,557
Commitments and Contingencies
Total stockholders’ equity	1,110,865	1,634,918
Total liabilities and equity	3,919,580	4,190,699
Debtor's
Current assets:
Cash and cash equivalents	75	$ 805
Trade and other receivables, net	11,550
Marine operating supplies	8,820
Other current assets	23,285
Total current assets	43,730
Investments in non-debtor subsidiaries	927,473
Net properties and equipment	755,492
Intercompany receivables from non-debtor subsidiaries	956,808
Other assets	106,167
Total assets	2,789,670
Current liabilities:
Accounts payable	6,909
Accrued expenses	23,878
Other current liabilities	1,175
Total current liabilities	31,962
Other liabilities and deferred credits	51,303
Intercompany payables to non-debtor subsidiaries	41,855
Liabilities subject to compromise	2,389,557
Commitments and Contingencies
Total stockholders’ equity	274,993
Total liabilities and equity	$ 2,789,670