CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Current assets:
Allowance for doubtful accounts of	$ 2,398	$ 1,820
Equity:
Preferred stock, authorized (in shares)	4,000,000	4,000,000
Preferred stock, par value (in dollars per share)	$ 1.00	$ 1.00
Common stock, authorized (in shares)	40,000,000	40,000,000
Common stock, par value (in dollars per share)	$ 0.20	$ 0.20
Common stock, issued (in shares)	22,711,448	22,646,822
Common stock, outstanding (in shares)	22,711,448	22,646,822