Fair Value Measurement of Financial Instruments (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended			12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Nov. 30, 2016	Dec. 04, 2015
Impairment of trademark	$ 17,900		$ 36,500	$ 17,899	$ 340,628
Goodwill impairment charge		$ 304,100			304,123
Maximum LIBOR rate above strike to trigger interest payments to Company				1.50%
Gross licensing revenue payable, percentage				3.50%
Amortization expense				$ 1,200	900	$ 1,300
Trademarks [Member]
Impairment of trademark				17,899	36,505
Amortization expense				300
Maximum [Member]
Impairment of trademark					100
Maximum [Member] | Trademarks [Member]
Amortization expense					100
Interest Rate Cap [Member]
Derivative, notional amount				$ 500,000			$ 500,000
Derivative, cap interest rate				1.50%
Derivative, maturity date				Nov. 23, 2018
Martha Stewart Living Omnimedia [Member]
Acquisition date fair value of Legacy Payments		$ 2,300		$ 2,600	2,300			$ 1,700
Interest Expense [Member]
Accretion expense				$ 300	$ 300