Fair Value Measurements (Details Textual) - USD ($)	3 Months Ended									12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	[1]	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Indefinite-Lived License Agreements	$ 95,250,000				$ 93,259,000					$ 95,250,000	$ 93,259,000	$ 96,229,000
Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill)	$ 0	$ 0	$ 0	$ 0	1,449,000	$ 0	$ 0	$ 0		$ 0	1,449,000	$ 0
Other Intangible Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Indefinite-Lived License Agreements					3,649,000						3,649,000
Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill)											1,449,000
Other Intangible Assets [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure					$ 2,200,000						$ 2,200,000

[1] March 31, 2017 quarterly data have been reclassified to conform with current presentation.