Investments Investments (Details) - USD ($)		3 Months Ended			6 Months Ended	9 Months Ended		12 Months Ended
	May 17, 2017	Sep. 30, 2018	Jun. 30, 2018	Sep. 30, 2017	Jun. 30, 2018	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Mar. 14, 2017	Aug. 15, 2016
Investment [Line Items]
Investment in Miso Robotics		$ 6,000,000						$ 2,250,000
Percentage of ownership, Miso Robotics		30.00%				30.00%		22.60%
Maximum Investment in Veritone										$ 50,000,000
Secured Convertible Promissory Note										20,000,000
Secured Promissory Note Advance										$ 10,000,000
Time-sharing Transactions, Stated Interest Rate for Notes Receivable										6.00%
First Loan Warrant										$ 700,000
Debt Instrument, Convertible, Conversion Price	$ 13.6088
Loan receivable and accrued interest	$ 20,700,000
Common stock, shares outstanding		49,639,319				49,639,319		50,639,926
Veritone Primary Warrant										$ 50,000,000
Cash paid for primary warrant exercise	$ 29,300,000
10% Warrant	809,400
Veritone Bridge Loan	$ 4,000,000								$ 4,000,000
Bridge loan stated interest rate									8.00%
Veritone Bridge Loan Advance 1									$ 1,000,000
Veritone Bridge Loan Advance 3 and 4									$ 2,000,000
Upfront Shares									60,000
Bridge Installment Shares									90,000
Bridge Warrant Share									157,000
Interest Income, Other				$ 1,100,000
Accretion (Amortization) of Discounts and Premiums, Investments							$ 630,000
Percentage of ownership, Veritone	20.00%
Shares of Investment Sold		1,000,000
Sale of Stock, Price Per Share		$ 10.44				$ 10.44
Investments at fair value		$ 36,648,000				$ 36,648,000		$ 104,754,000
Revenues		13,725,000		36,633,000		82,303,000	61,944,000
Net Income (Loss) Available to Common Stockholders, Diluted		$ (33,195,000)		$ 158,326,000		$ (93,660,000)	$ 132,143,000
Earnings Per Share, Basic		$ (0.67)		$ 3.13		$ (1.87)	$ 2.62
Assets, Current		$ 157,103,000				$ 157,103,000		139,695,000
Total assets		220,276,000				220,276,000		308,768,000
Current liabilities		16,260,000				16,260,000		9,557,000
Total liabilities		18,134,000				18,134,000		13,109,000
Stockholders' Equity Attributable to Parent		$ 200,298,000				$ 200,298,000		294,301,000
Equity Method Investment, Ownership Percentage		15.00%				15.00%
Cumulative Unrealized Gain (Loss) Since Inception		$ 8,140,000				$ 8,140,000
Minimum [Member]
Investment [Line Items]
Receivable with Imputed Interest, Effective Yield (Interest Rate)						9.00%
Maximum [Member]
Investment [Line Items]
Fair Value Assumptions, Expected Volatility Rate						50.00%
Fair Value Inputs, Probability of Default						75.00%
Fair value inputs recovery						100.00%
Receivable with Imputed Interest, Effective Yield (Interest Rate)							53.00%
Veritone [Member]
Investment [Line Items]
Investment Income, Interest						$ 21,000
Revenues			$ 4,168,000		$ 8,556,000
Gross Profit			3,348,000		7,172,000
Operating Expenses			17,081,000		34,855,000
Other Operating Income (Expense), Net			133,000		316,000
Net Income (Loss) Available to Common Stockholders, Diluted			$ (14,330,000)		$ (27,379,000)
Earnings Per Share, Basic			$ (880)		$ (1,690)
Assets, Current			$ 97,833,000		$ 97,833,000			83,805,000
Noncurrent assets			7,190,000		7,190,000			4,753,000
Total assets			105,023,000		105,023,000			88,558,000
Current liabilities			32,027,000		32,027,000			27,256,000
Noncurrent liabilities			473,000		473,000			0
Total liabilities			32,500,000		32,500,000			27,256,000
Preferred Stock, Value, Outstanding			0		0			0
Stockholders' Equity Attributable to Parent			72,523,000		72,523,000			61,302,000
Total liabilities, preferred stock and stockholders' equity			$ 105,023,000		$ 105,023,000			$ 88,558,000
Common Stock [Member]
Investment [Line Items]
Investment Owned, Balance, Shares								3,119,521
Investments at fair value		32,538,000				32,538,000
Warrant [Member]
Investment [Line Items]
Investment Owned, Balance, Shares								1,120,432
Investments at fair value		$ 4,110,000				$ 4,110,000
Veritone Loans [Member] | Veritone [Member]
Investment [Line Items]
Common stock, shares outstanding	1,523,746
Primary warrant [Member] | Veritone [Member]
Investment [Line Items]
Common stock, shares outstanding	2,150,335
Bridge Loan [Member] | Veritone [Member]
Investment [Line Items]
Common stock, shares outstanding	295,440
Finnerty - Common Stock [Member]
Investment [Line Items]
Fair Value Assumptions, Expected Volatility Rate	35.00%	0.00%						37.00%
Fair Value Inputs, Discount for Lack of Marketability	6.00%	0.00%						5.00%
Fair Value Assumptions, Expected Term	6 months	0 months						2 months
Monte Carlo [Member] | Minimum [Member]
Investment [Line Items]
Fair Value Assumptions, Expected Volatility Rate						40.00%
Fair Value Inputs, Probability of Default						25.00%
Fair Value Inputs, Discount for Lack of Marketability						7.00%
Finnerty [Member]
Investment [Line Items]
Fair Value Assumptions, Expected Term						4 years
Finnerty [Member] | Minimum [Member]
Investment [Line Items]
Fair Value Inputs, Discount for Lack of Marketability						27.00%
Finnerty [Member] | Maximum [Member]
Investment [Line Items]
Fair Value Inputs, Discount for Lack of Marketability						30.00%
Black Scholes [Member]
Investment [Line Items]
Fair Value Assumptions, Expected Dividend Payments						$ 0
Black Scholes [Member] | Minimum [Member]
Investment [Line Items]
Fair Value Assumptions, Expected Volatility Rate						70.00%
Fair Value Assumptions, Risk Free Interest Rate						2.81%
Fair Value Assumptions, Expected Term						2 years
Black Scholes [Member] | Maximum [Member]
Investment [Line Items]
Fair Value Assumptions, Risk Free Interest Rate						3.03%
Fair Value Assumptions, Expected Term						9 years
Finnerty - Warrants [Member]
Investment [Line Items]
Fair Value Assumptions, Expected Volatility Rate	35.00%
Fair Value Inputs, Discount for Lack of Marketability	6.00%							10.00%
Fair Value Assumptions, Expected Term	6 months	2 years						5 months
Finnerty - Warrants [Member] | Minimum [Member]
Investment [Line Items]
Fair Value Assumptions, Expected Volatility Rate		70.00%						72.00%
Fair Value Inputs, Discount for Lack of Marketability		20.00%
Finnerty - Warrants [Member] | Maximum [Member]
Investment [Line Items]
Fair Value Assumptions, Expected Volatility Rate								87.00%
Fair Value Inputs, Discount for Lack of Marketability		31.00%