Fair Value Disclosures - Fair Value Measurements on Recurring Basis (Detail) (USD $)	Sep. 30, 2013
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Total trading securities	$ 4,867,000
Total available-for-sale securities	8,224,000
Total Investments	13,091,000
Common Stock [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Total trading securities	23,000
Total available-for-sale securities	1,739,000
Offshore Fund [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Total trading securities	902,000
Total available-for-sale securities	4,778,000
Mutual funds [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Total trading securities	3,942,000
Total available-for-sale securities	1,544,000
Venture Capital Investments [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Total available-for-sale securities	163,000
Quoted Prices (Level 1) [Member] \| Recurring basis [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Total trading securities	3,965,000
Total available-for-sale securities	3,186,000
Total Investments	7,151,000
Quoted Prices (Level 1) [Member] \| Common Stock [Member] \| Recurring basis [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Total trading securities	23,000
Total available-for-sale securities	1,642,000
Quoted Prices (Level 1) [Member] \| Offshore Fund [Member] \| Recurring basis [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Total trading securities
Total available-for-sale securities
Quoted Prices (Level 1) [Member] \| Mutual funds [Member] \| Recurring basis [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Total trading securities	3,942,000
Total available-for-sale securities	1,544,000
Quoted Prices (Level 1) [Member] \| Venture Capital Investments [Member] \| Recurring basis [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Total available-for-sale securities
Significant Other Inputs (Level 2) [Member] \| Recurring basis [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Total trading securities	902,000
Total available-for-sale securities	4,778,000
Total Investments	5,680,000
Significant Other Inputs (Level 2) [Member] \| Common Stock [Member] \| Recurring basis [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Total trading securities
Total available-for-sale securities
Significant Other Inputs (Level 2) [Member] \| Offshore Fund [Member] \| Recurring basis [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Total trading securities	902,000
Total available-for-sale securities	4,778,000
Significant Other Inputs (Level 2) [Member] \| Mutual funds [Member] \| Recurring basis [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Total trading securities
Total available-for-sale securities
Significant Other Inputs (Level 2) [Member] \| Venture Capital Investments [Member] \| Recurring basis [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Total available-for-sale securities
Significant Unobservable Inputs (Level 3) [Member] \| Recurring basis [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Total trading securities
Total available-for-sale securities	260,000
Total Investments	260,000
Significant Unobservable Inputs (Level 3) [Member] \| Common Stock [Member] \| Recurring basis [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Total trading securities
Total available-for-sale securities	97,000
Significant Unobservable Inputs (Level 3) [Member] \| Offshore Fund [Member] \| Recurring basis [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Total trading securities
Total available-for-sale securities
Significant Unobservable Inputs (Level 3) [Member] \| Mutual funds [Member] \| Recurring basis [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Total trading securities
Total available-for-sale securities
Significant Unobservable Inputs (Level 3) [Member] \| Venture Capital Investments [Member] \| Recurring basis [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Total available-for-sale securities	$ 163,000