Schedule II - Valuation and Qualifying Accounts (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	$ 10,867	$ 10,954	$ 14,688
Additions Charged to Costs and Expenses	32,718	29,424	29,858
Deductions	30,480	29,511	33,592
Balance at End of Period	13,105	10,867	10,954
Doubtful Accounts [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	192	318	308
Additions Charged to Costs and Expenses	31	198	10
Deductions	186	324	0
Balance at End of Period	37	192	318
Cash Discounts [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	241	259	573
Additions Charged to Costs and Expenses	25,801	25,207	26,620
Deductions	25,627	25,225	26,934
Balance at End of Period	415	241	259
Deferred Tax Valuation Allowance [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	6,014	6,310	9,752
Additions Charged to Costs and Expenses	0	0	0
Deductions	1,081	296	3,442
Balance at End of Period	4,933	6,014	6,310
Sales Returns [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	4,420	4,067	4,055
Additions Charged to Costs and Expenses	6,886	4,019	3,228
Deductions	3,586	3,666	3,216
Balance at End of Period	$ 7,720	$ 4,420	$ 4,067