Unaudited Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Mar. 31, 2012	Dec. 31, 2011
Common Class A [Member]
Common stock, par value	$ 1	$ 1
Common stock, shares outstanding	6,795,404	6,778,346
Common Class B [Member]
Common stock, par value	$ 1	$ 1
Common stock, shares outstanding	1,592,571	1,595,581