Consolidated Statements of Operations and Comprehensive Income (Parenthetical) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Change in employee benefit plan funded status, tax	$ 46,974	$ (16,894)	$ (19,498)
Prior service cost, tax	111	113	112
Actuarial loss, tax	$ 5,697	$ 4,668	$ 2,879