Summary of Significant Accounting Policies (Other Current Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
Accounting Policies [Abstract]
Accounts payable	$ 13,144		$ 18,552
Accrued promotional expenses	37,940		30,691
Accrued excise and payroll taxes payable, net	14,612		11,946
Accrued interest	38,673		33,138
Commissions payable	12,975		14,320
Accrued salaries and benefits	30,228		29,639
Allowance for sales returns	6,935		5,632
Other current liabilities	24,646		13,205
Total other current liabilities	$ 179,153	$ 167,454	$ 157,123