Accumulated Other Comprehensive Loss (Details Textual) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011	Jun. 30, 2011
Accumulated Other Comprehensive Loss (Textual) [Abstract]
Net unrealized gains on investment securities-available-for-sale, tax expense	$ 2,051	$ 1,796	$ 2,025
Pension and other postretirement benefits adjustment, tax benefit	$ 15,062	$ 15,435	$ 9,258