Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in equity securities classified as available-for-sale.

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Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in equity securities classified as available-for-sale.

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This item represents the cost of equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments for other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

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Amount of equity securities categorized neither as held-to-maturity nor as trading.

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Balance held at close of period in number of shares.

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Nominal or face amount on the investment owned.

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Sum of the carrying values as of the balance sheet date of the portions of long-term notes payable due within one year or the operating cycle if longer.

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The amount by which the fair value of an investment in debt and equity securities categorized as Available-for-sale is less than the amortized cost basis or carrying amount of that investment at the balance sheet date and the decline in fair value is deemed to be other than temporary, before considering whether or not such amount is recognized in earnings or other comprehensive income.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Securities Available-for-Sale (Detail) £ in Thousands, $ in Thousands, shares in Millions	12 Months Ended
	Jun. 30, 2015 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2016 GBP (£)	Sep. 09, 2016 GBP (£)	Aug. 11, 2016 GBP (£) shares	Jun. 30, 2016 USD ($)	Apr. 15, 2016 USD ($)
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	$ 4,230	$ 1,810				$ 885
Gross unrealized gains	0	279				0
Gross unrealized losses	0	(191)				(284)
Fair value	4,230	1,898				601
Notes payable	0	$ 104				$ 783
One Stone \| One Stone Exchange Agreement \| Investor
Schedule of Available-for-sale Securities [Line Items]
Notes payable							$ 625
Central Petroleum Limited
Schedule of Available-for-sale Securities [Line Items]
Impairment on AFS securities	14,900
Other investment
Schedule of Available-for-sale Securities [Line Items]
Impairment on AFS securities	$ 171
Weald ATA, IoW ATA, and Settlement Agreement \| Subsidiary \| UKOG \| UK Oil and Gas Investments
Schedule of Available-for-sale Securities [Line Items]
Investment owned, value \| £			£ 930	£ 958	£ 703
Shares issued (in shares) \| shares					50.9