CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
CONSOLIDATED BALANCE SHEETS
Allowances on accounts receivable (in dollars)	$ 1,160	$ 1,078
Accumulated depreciation on property and equipment (in dollars)	69,957	64,345
Accumulated amortization on intangible assets (in dollars)	$ 2,307	$ 2,223
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, shares issued	20,500,394	20,405,044
Common stock, shares outstanding	20,500,394	20,405,044