Unaudited Condensed Consolidated Statements of Comprehensive Income (Parenthetical) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Statement of Comprehensive Income [Abstract]
Tax expense on current period cash flow hedging activity	$ 356	$ 541	$ 432	$ 16
Tax expense (benefit) on reclassification of hedging activities into earnings	(77)	1,071	(170)	2,293
Tax benefit on reclassification of pension and postretirement into earnings	$ 264	$ 542	$ 408	$ 1,114