Accounting for Certain Loans Acquired in a Purchase - Narrative (Details) (USD $) In Millions, unless otherwise specified	Feb. 10, 2012 SCB Bank	Nov. 12, 2013 Merger with CFS Bancorp, Inc. (Citizens)
Business Acquisition [Line Items]
Loan Acquired during acquisition	$ 113.0	$ 639.6
Fair Value Discount	$ 19.2	$ 36.5