Acquisitions and Dispositions Acquisitions (Details) (USD $)	0 Months Ended
	Sep. 02, 2013 Locations	Dec. 31, 2014
Summit acquisition, branch locations acquired		350
Summit Acquisition [Member]
Summit acquisition, consideration transferred	$ 43,200,000
Summit acquisition, assets acquired	261,600,000
Summit acquisition, loans acquired	207,400,000
Summit acquisition, deposits acquired	232,300,000
Summit acquisition, branch locations acquired	2
Summit acquisition, Goodwill recognized in acquisition	13,300,000
Summit acquisition, Core deposit premium recognized in acquired	5,600,000
Summit acquisition, Goodwill, Expected Tax Deductible Amount		$ 0