Consolidated Statements Of Comprehensive Income (Parenthetical) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Statement of Other Comprehensive Income [Abstract]
Unrealized investment gains - taxes	$ 191	$ 77	$ 0
Realized investment gains - taxes	(171)	0	0
Change in unfunded benefit obligation for pension and other postretirement benefit plans - taxes	$ (590)	$ (778)	$ (1,064)