Commitments and Contingencies (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Restricted Cash and Cash Equivalents	$ 0				$ 11,512,000				$ 0	$ 11,512,000
Rent expense									1,392,000	1,795,000	$ 1,926,000
Other	1,200,000	$ 0	$ 0	$ 0	0	$ 0	$ (1,242,000)	$ 1,742,000	1,200,000	500,000	$ 4,141,000
Cash and other assets, IP Fund	986,000				1,118,000				986,000	1,118,000
Investments, IP Fund	1,905,000				2,933,000				1,905,000	2,933,000
Total assets, IP Fund	2,891,000				4,051,000				2,891,000	4,051,000
Accrued expenses and contributions, IP Fund	2,567,000				2,394,000				2,567,000	2,394,000
Net assets, IP Fund	324,000				$ 1,657,000				324,000	1,657,000
Revenues, IP Fund									0	16,000
IP Fund, Operating expenses									390,000	572,000
IP Fund, Gain from Operations									(390,000)	(556,000)
IP Fund, Net Loss in Equity Method Investment									(943,000)	(1,013,000)
IP Fund, Net Loss									(1,333,000)	$ (1,569,000)
Minimum [Member]
Loss Contingency, Estimate of Possible Loss	1,200,000								1,200,000
Maximum [Member]
Loss Contingency, Estimate of Possible Loss	$ 3,000,000								$ 3,000,000