Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Consolidated Balance Sheets [Abstract]
Accounts receivable, allowance for doubtful accounts	$ 1,606	$ 1,755
Preferred stock, no par value
Preferred stock, authorized shares	10,000	10,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, no par value
Common stock, authorized shares	240,000	240,000
Common stock, shares issued	69,646	90,988
Common stock, shares outstanding	69,646	90,988