Investments (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Schedule of Available-for-sale Securities
Debt securities, Cost	$ 12,162,000		$ 12,162,000		$ 8,988,000
Debt securities, Carrying Value	12,340,000		12,340,000		9,172,000
Total, Cost	37,654,000		37,654,000		40,011,000
Total, Gross Unrealized Gains	11,440,000		11,440,000		11,048,000
Total, Gross Unrealized Losses	(215,000)		(215,000)		(479,000)
Total, Carrying Value	48,879,000		48,879,000		50,580,000
Available-for-sale Securities, Continuous Unrealized Loss Position
Less than 12 months, fair value	5,401,000		5,401,000		4,453,000
Less than 12 months, Gross Unrealized Loss	142,000		142,000		254,000
Greater than 12 months, fair value	692,000		692,000		8,112,000
Greater than 12 months, Gross Unrealized Loss	73,000		73,000		225,000
Available-for-sale Securities, Debt Maturities [Abstract]
Due in one year or less, Amortized Cost	1,961,000		1,961,000		68,000
Due after one year through five years, Amortized Cost	7,864,000		7,864,000		5,981,000
Due after five years, Amortized Cost	2,337,000		2,337,000		2,939,000
Due in one year or less, Carrying Value	1,961,000		1,961,000		68,000
Due after one year through five years, Carrying Value	7,981,000		7,981,000		6,178,000
Due after five years, Carrying Value	2,398,000		2,398,000		2,926,000
Other Investments [Abstract]
Equity in loss of unconsolidated affiliate	(681,000)		(1,160,000)
Mindjet
Other Investments [Abstract]
Voting Interest Percentage	28.60%		28.60%
Equity Method Investment, Ownership Percentage	15.10%		15.10%
Cost Method, Ownership Percentage	13.50%		13.50%
Other Investments	26,600,000		26,600,000
Corporate Bond Securities [Member]
Schedule of Available-for-sale Securities
Debt securities, Cost	12,162,000		12,162,000		8,988,000
Debt securities, Gross Unrealized Gains	307,000		307,000		213,000
Debt securities, Gross Unrealized Losses	(129,000)		(129,000)		(29,000)
Debt securities, Carrying Value	12,340,000		12,340,000		9,172,000
Available-for-sale Securities, Continuous Unrealized Loss Position
Less than 12 months, fair value	5,201,000		5,201,000
Less than 12 months, Gross Unrealized Loss	129,000		129,000
Greater than 12 months, fair value					5,744,000
Greater than 12 months, Gross Unrealized Loss					29,000
Convertible Debt Securities | Mindjet
Other Investments [Abstract]
Payments to Acquire Held-to-maturity Securities	1,800,000
Escrow Deposit	730,000		730,000
Investment Interest Rate			10.00%
Convertible debt conversion ratio			3
Equity Securities [Member]
Schedule of Available-for-sale Securities
Marketable equity securities, Cost	25,492,000		25,492,000		31,023,000
Marketable equity securities, Gross Unrealized Gains	11,133,000		11,133,000		10,835,000
Marketable equity securities, Gross Unrealized Losses	(86,000)		(86,000)		(450,000)
Marketable equity securities, Carrying Value	36,539,000		36,539,000		41,408,000
Available-for-sale Securities, Continuous Unrealized Loss Position
Less than 12 months, fair value	200,000		200,000		4,453,000
Less than 12 months, Gross Unrealized Loss	13,000		13,000		254,000
Greater than 12 months, fair value	692,000		692,000		2,368,000
Greater than 12 months, Gross Unrealized Loss	73,000		73,000		196,000
Available-for-sale Securities, Debt Maturities [Abstract]
Impairment losses, available-for-sale securities		$ 917,000