Summary of Significant Accounting Policies (Other Current Liabilities) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Jan. 01, 2018	Dec. 31, 2017
Accounting Policies [Abstract]
Accounts payable	$ 12,158		$ 18,552
Accrued promotional expenses	32,282		30,691
Accrued excise and payroll taxes payable, net	777		11,946
Accrued interest	20,124		33,138
Commissions payable	16,475		14,320
Accrued salary and benefits	24,304		29,639
Contract liabilities	8,043	$ 4,667	0
Allowance for sales returns	6,945		5,632
Other current liabilities	19,301		13,205
Total other current liabilities	$ 140,409	$ 167,454	$ 157,123