Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Consolidated Balance Sheets
Accounts receivable, allowances (in dollars)	$ 1,567	$ 1,752
Property and equipment, accumulated depreciation (in dollars)	$ 50,069	$ 47,859
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized	1,000	1,000
Preferred stock, shares issued	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	100,000	100,000
Common stock, shares issued	75,457	74,487
Treasury stock, shares	96	708