Fair Value Measurements (Details Textual) - USD ($)	3 Months Ended														12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	[1]	Dec. 31, 2016		Sep. 30, 2016	[1]	Jun. 30, 2016	[1]	Mar. 31, 2016	[1]	Dec. 31, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Indefinite-Lived License Agreements	$ 93,259,000					$ 86,622,000								$ 88,106,000	$ 93,259,000	$ 86,622,000	$ 88,106,000
Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill)	1,449,000	$ 0	$ 0	$ 0		$ 0	[1]	$ 0		$ 0		$ 0		874,000	1,449,000	$ 0	874,000
Other Intangible Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Indefinite-Lived License Agreements	3,649,000													13,282,000	3,649,000		13,282,000
Assets, Fair Value Disclosure, Nonrecurring	2,200,000													12,408,000	$ 2,200,000		$ 12,408,000
Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill)	$ 1,449,000													$ 874,000

[1] Certain prior year amounts and March 31, 2017 quarterly data have been reclassified to conform with current presentation.