Consolidated Balance Sheets Consolidated Balance Sheets Parentheticals (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Assets [Abstract]
Allowance for Doubtful Accounts Receivable, Current	$ 1,105	$ 1,128
Allowance for Doubtful Other Receivables, Current	0	8
Liabilities and shareholders' equity
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, authorized (in shares)	100,000,000	100,000,000
Common stock, shares issued	60,961,570	60,702,342
Common stock, outstanding (in shares)	60,355,545	60,291,939
Treasury stock, at cost (in shares)	606,025	410,403
Limited Liability Company [Member]
Assets [Abstract]
Allowance for Doubtful Accounts Receivable, Current	1,105	1,128
Allowance for Doubtful Other Receivables, Current	$ 0	$ 8