Condensed Consolidated Statements of Comprehensive Income (Parenthetical) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Tax expense recognized on the amortization of prior service cost	$ (6)	$ (6)	$ (12)	$ 12
Tax expense recognized on the net gain (loss)	(27)	43	(53)	81
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax	$ (1)		$ (1)