Intangible Assets (Net Carrying Value) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Jun. 30, 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	12,454		13,424	14,354
Core deposit intangible assets [Member]
Other intangible assets:
Total other intangible assets	9,110		10,001	10,933
Mortgage servicing rights [Member]
Other intangible assets:
Total other intangible assets	$ 3,344	$ 3,316	$ 3,423	$ 3,421	$ 3,485	$ 3,478