Investments - Additional Information (Details) $ in Thousands		12 Months Ended
		Jun. 30, 2015 USD ($) security	Jun. 30, 2014 USD ($)	Jun. 30, 2013 USD ($)	Dec. 31, 2013 USD ($)
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Fair value of investments held		$ 19,903
Cost basis of investments held		$ 21,100
Market value of investments to Company's total assets		64.70%
Other investments		$ 2,303	$ 1,413
Trading, fair value	[1]	15,640	17,817
Other-than-temporary impairments		247	3	$ 47
Available-for-sale, amortized cost	[2],[3]	4,602	4,851
Available-for-sale securities, fair value	[2],[3]	$ 4,263	$ 6,196
Percentage of financial assets derived from Level 1 inputs measured at fair value		94.00%	90.00%
Percentage of financial assets derived from Level 2 inputs measured at fair value		3.00%	9.00%
Percentage of financial assets derived from Level 3 inputs measured at fair value		3.00%	1.00%
Private and venture capital securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Investments transferred out of Level 3 assets			$ 385
Offshore fund [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Trading, fair value	[1]	$ 481	998
Corporate debt securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Available-for-sale, amortized cost	[3]	1,433	1,706
Available-for-sale securities, fair value	[3]	616	1,632
Investments transferred out of Level 3 assets		0	0
Investments transferred into level 3 assets		$ 343	0
Corporate debt securities, one [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Number of positions, subject to impairment loss | security		1
Available-for-sale, amortized cost		$ 44
Available-for-sale securities, fair value		5
Other securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Trading, fair value	[1]	$ 0	27
Number of positions, subject to impairment loss | security		2
Available-for-sale, amortized cost	[3]	$ 169	232
Available-for-sale securities, fair value	[3]	163	240
Investments transferred out of Level 3 assets			285
Investments transferred into level 3 assets			0
Other securities, one [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Available-for-sale, amortized cost		310
Available-for-sale securities, fair value		234
Other securities, two [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Available-for-sale, amortized cost		1,102
Available-for-sale securities, fair value		970
Government Fund [Member] | Mutual funds [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Trading, fair value					$ 14,100
Available-for-sale Securities [Member] | Corporate debt securities [Member] | Significant Other Inputs (Level 2) [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Available-for-sale securities, fair value		$ 77	1,100
Trading Securities [Member] | Offshore fund [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Minimum redemption notice		45 days
Trading Securities [Member] | Offshore fund [Member] | Significant Other Inputs (Level 2) [Member] | Energy and natural resource sectors [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Trading, fair value		$ 481	$ 998

[1] Unrealized and realized gains and losses on trading securities are included in earnings in the statement of operations.

[2] Net unrealized gains (losses) on available-for-sale securities gross and net of tax as of June 30, 2015, are $(339) and $(339), respectively, and as of June 30, 2014, are $1,345 and $888, respectively.

[3] Unrealized gains and losses on available-for-sale securities are excluded from earnings and recorded in other comprehensive income (loss) as a separate component of shareholders’ equity until realized.