Accumulated Other Comprehensive Loss (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012	Jun. 30, 2012
Components of accumulated other comprehensive loss, net of related tax benefit/expense
Net unrealized gains (losses) on investment securities – available-for-sale, net of related tax expense (benefit) of $(486) at June 30, 2013, $2,301 at December 31, 2012 and $2,051 at June 30, 2012	$ (905)	$ 4,274	$ 3,810
Pension and other postretirement benefits adjustment, net of related tax benefit of $18,394 at June 30, 2013, $19,058 at December 31, 2012 and $15,062 at June 30, 2012	(34,160)	(35,393)	(27,974)
Accumulated other comprehensive loss	$ (35,065)	$ (31,119)	$ (24,164)