Consolidated Statements of Comprehensive Income (Unaudited) (Parenthetical) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Other comprehensive (loss) income, before tax
Unrealized net holding (losses) gains arising during the period, pre-tax amounts	$ (6,927)	$ 1,463	$ (33,391)	$ 1,798
Reclassification adjustment for net gains related to securities available for sale included in net income, pre-tax amounts	329	26	1,413	578
Amortization of prior service cost and actuarial gains, pre-tax amounts	709	989	2,244	2,702
Increase in unrecognized actuarial loss, pre-tax amounts	$ 4,036	$ 0	$ 4,036	$ 0