Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Per Share data, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Allowance for doubtful accounts receivable	$ 4,477	$ 4,856
Preferred stock, par value	$ 100.00	$ 100.00
Preferred stock, shares authorized	750	750
Preferred stock, shares issued	0	0
Common stock, par value	$ 0.50	$ 0.50
Common stock, shares authorized	500,000	500,000
Common stock, shares issued	32,338	32,338
Treasury stock, shares	5,416	5,714