Consolidated Balance Sheets Parenthetical (USD $) In Thousands, except Share data, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Current assets:
Allowance for doubtful accounts	$ 10,304	$ 10,413
Shareholders’ equity:
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, par value (USD per share)	$ 0	$ 0
Preferred stock, shares issued	0	0
Common stock, shares authorized	200,000,000	200,000,000
Common stock, stated value (USD per share)	$ 1	$ 1
Common stock, shares issued	60,614,741	60,614,741
Treasury stock, shares	4,336,351	5,071,125