CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (unaudited) (Parenthetical) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Statement of Comprehensive Income [Abstract]
Net actuarial pension (loss) gain, tax	$ 6,811	$ 242	$ 3,709
Actuarial pension loss amortization, tax	790	1,062	704
Prior service cost (credit) amortization, tax	604	607	607
Pension settlement (loss), tax	17	309	470
Unrealized gains (losses) on available-for-sale securities, tax	$ 0	$ 0	$ 0