Intangible Assets (Net Carrying Value) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013	Dec. 31, 2012
Net carrying value of intangible assets
Goodwill	$ 120,164	$ 120,164	$ 120,164
Other intangible assets:
Total other intangible assets	12,872	13,424	14,902
Core deposit intangible assets [Member]
Other intangible assets:
Total other intangible assets	9,556	10,001	11,417
Mortgage servicing rights [Member]
Other intangible assets:
Total other intangible assets	$ 3,316	$ 3,423	$ 3,485	$ 3,478