Intangible Assets (Carrying and Fair Value of MSRs) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2012
Net carrying value, fair value of MSRs and loans Corporation servicing for others
Loans serviced for others that have servicing rights capitalized	$ 886,980	$ 906,314	$ 901,052
Mortgage servicing rights [Member]
Net carrying value, fair value of MSRs and loans Corporation servicing for others
Net carrying value of MSRs	3,399	3,478	3,466
Fair value of MSRs	$ 6,839	$ 4,716	$ 4,277