Summary of Significant Accounting Policies (Other Current Liabilities) (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Accounts payable	$ 11,704		$ 13,144
Accrued promotional expenses	30,909		37,940
Accrued excise and payroll taxes payable, net	12,710		14,612
Accrued interest	27,571		38,673
Commissions payable	18,199		12,975
Accrued salary and benefits	13,352		30,228
Contract liabilities	7,824	$ 7,071	0
Allowance for sales returns	7,318		6,935
Other current liabilities	23,747		24,646
Total other current liabilities	$ 153,334		$ 179,153