Miscellaneous Financial Information (Unaudited), Dividends and Preferred Stock Redemption (Details) (USD $)	0 Months Ended	1 Months Ended		0 Months Ended	12 Months Ended
	Jan. 27, 2012 Common Stock [Member]	Oct. 31, 2011 Common Stock [Member]	Apr. 30, 2011 Common Stock [Member]	Jun. 24, 2011 Cumulative Preferred Stock, $100 Par Value, Not subject to mandatory redemption 4.5% [Member]	Dec. 31, 2011 Cumulative Preferred Stock, $100 Par Value, Not subject to mandatory redemption 4.5% [Member]
Dividends Payable [Line Items]
Dividend payable (in dollars per share)	$ 0.3125	$ 0.3125	$ 0.28
Dividend, declaration date	Jan. 27, 2012
Dividend, declaration date		2011-10	2011-04
Dividend, payable date	Feb. 15, 2012	Nov. 15, 2011	May 16, 2011
Dividend, date of record	Feb. 06, 2012
Redemption date					Jun. 24, 2011
Preferred stock redeemed (in shares)				10,288
Preferred stock not subject to mandatory redemption, dividend rate (in hundredths)				4.50%
Redemption price (in dollars per share)				$ 101
Redemption price, plus accrued and unpaid dividends to the redemption date (in dollars per share)				$ 101.296