Schedule II - Valuation and Qualifying Accounts (Valuation and Qualifying Accounts) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Sales returns and allowances [Member]
Balance at beginning of period	$ 7,326		$ 6,406		$ 5,634
Additions - charged to costs and expenses	(826)		920		772
Additions - charged to other accounts - describe	0		0		0
Deductions - describe	0		0		0
Balance at end of period	6,500		7,326		6,406
Allowance for doubtful accounts [Member]
Balance at beginning of period	6,447		6,403		8,349
Additions - charged to costs and expenses	8,499		8,043		7,695
Additions - charged to other accounts - describe	0		0		0
Deductions - describe	8,285	[1]	7,999	[1]	9,641	[1]
Balance at end of period	$ 6,661		$ 6,447		$ 6,403

[1] Uncollectable accounts written off.