Statements Of Consolidated Comprehensive Income (Parenthetical) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Statement of Income and Comprehensive Income [Abstract]
Unrealized gain on available-for-sale security, deferred tax	$ 182	$ 7	$ 145	$ 21
Amortization of actuarial loss included in expense, deferred tax	$ 1,872	$ 976	$ 5,633	$ 2,928