CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
CONSOLIDATED BALANCE SHEETS
Accounts receivable, allowances (in dollars)	$ 1,184	$ 1,305
Property and equipment, accumulated depreciation (in dollars)	94,680	88,042
Intangible assets, accumulated amortization (in dollars)	$ 2,642	$ 2,558
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, authorized shares	4,000,000	4,000,000
Preferred stock, issued shares	0	0
Preferred stock, outstanding shares	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, authorized shares	100,000,000	100,000,000
Common stock, issued shares	20,981,098	20,747,161
Common stock, outstanding shares	20,981,098	20,747,161