CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Accounts receivable, less allowance for doubtful accounts	$ 22,671	$ 22,716
Common stock, par value	$ 0.10	$ 0.10
Common stock, authorized	100,000,000	100,000,000
Common stock, issued	74,435,628	74,435,628
Treasury stock, shares	34,605,362	34,116,220