Schedule II - Valuation and Qualifying Accounts (Valuation and Qualifying Accounts) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Sales returns and allowances [Member]
Valuation and Qualifying Accounts
Balance at beginning of period		$ 6,855	$ 6,500	$ 7,326
Additions - charged to costs and expenses		1,123	355	(826)
Additions - charged to other accounts - describe		0	0	0
Deductions - describe		0	0	0
Balance at end of period		7,978	6,855	6,500
Allowance for doubtful accounts [Member]
Valuation and Qualifying Accounts
Balance at beginning of period		8,713	6,661	6,447
Additions - charged to costs and expenses		7,119	8,919	8,499
Additions - charged to other accounts - describe		0	0	0
Deductions - describe	[1]	6,195	6,867	8,285
Balance at end of period		$ 9,637	$ 8,713	$ 6,661

[1] Uncollectable accounts written off.