Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Consolidated Balance Sheets [Abstract]
Allowance for doubtful accounts receivable	$ 4,295	$ 4,615
Preferred stock, par value	$ 100	$ 100
Preferred stock, shares authorized	750,000	750,000
Preferred stock, shares issued	0	0
Common stock, par value	$ 0.50	$ 0.5
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	32,338,000	32,338,000
Treasury stock, shares	5,533,000	5,048,000