CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
CONSOLIDATED BALANCE SHEETS
Allowances on accounts receivable (in dollars)	$ 1,078	$ 947
Accumulated depreciation on property and equipment (in dollars)	64,345	46,878
Accumulated amortization on intangible assets (in dollars)	$ 2,223	$ 1,888
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	20,405,044	20,007,081
Common stock, outstanding shares	20,405,044	20,007,081