Condensed Consolidated Statements of Income and Comprehensive Income (Parenthetical) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Amortization of losses from pension and postretirement benefit plans, income tax expense	$ 1,482	$ 927	$ 2,850	$ 1,854