Stockholder's Equity (Details) (USD $)
Share data in Millions, except Per Share data, unless otherwise specified

12 Months Ended

Dec. 31, 2011

Dec. 31, 2010

Dec. 31, 2009

Oct. 12, 2007

Stockholders's Equity (Textuals) [Abstract]

Cash dividends declared per common share

$ 0.775

$ 0.485

$ 0.44

Convertible debebtures

$ 14,000,000

$ 2,000,000

$ 28,000,000

Debentures converted into shares

1

1

3

Exercise price of right

$ 50

Share of series A junior participating preferred stock available under each right

one two-hundredth

Minimum percentage for exercising right

15.00%

Threshold percentage to divest of common stock

14.90%

Redeemed price if rights have not exercised and expired in 2014

0.01

Minimum percentage of assets cash flow and earning power sold

50.00%

Each holder of a right shall have the right to receive, upon exercise, common stock of the acquiring company having a value

equal to two times the exercise price of the right

Jr. Subordinated Convertible Debt [Member]

Debt Instrument [Line Items]

Junior subordinated convertible debentures

5.50%

Converted common stock outstanding

1

Original amount status

300,000,000

Outstanding amount of debt to be used for conversion in to shares

$ 8,000,000