Consolidated Statements of Equity (Parenthetical) (USD $) Share data in Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Income tax on unrecognized actuarial loss (gain) and prior service costs	$ 10,293,000
Income tax on cash flow hedge activity	21,000	112,000	134,000
Treasury shares purchased			20
Stock option exercises and other shares issued to employees and directors, shares		157	171
Dividends declared, per common share	$ 0.4810	$ 0.3575	$ 0.3475
Additional Paid-in Capital
Stock option exercises and other shares issued to employees and directors, shares	150	157	171
Income tax on stock option exercise and other shares issued to employees and director	1,197,000	1,076,000	826,000
Treasury Shares
Treasury shares purchased	85		20
Stock option exercises and other shares issued to employees and directors, shares	150	157	171
Income tax on stock option exercise and other shares issued to employees and director	1,197,000	1,076,000	826,000
Accumulated Other Comprehensive Loss
Income tax on unrecognized actuarial loss (gain) and prior service costs	10,293,000	3,116,000	2,431,000
Income tax on estimated fair value of investment in debt securities	1,710,000	1,004,000
Income tax on cash flow hedge activity	$ 21,000	$ 112,000	$ 134,000
Retained Earnings
Dividends declared, per common share	$ 0.4810	$ 0.3575	$ 0.3475