Acquired and Covered Loans (Details) - Narrative $ in Millions	12 Months Ended
	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($) transaction	Dec. 31, 2014 USD ($)
Acquired Loans [Abstract]
Number Of FDIC Assisted Transactions With Expired Loss Share Agreements Relating To Non-residential Mortgage Loans | transaction		3
Non-residential Mortgage Loans With Expired Loss Share Agreements	$ 14.9	$ 21.0
Renewed non-purchased credit impaired loans	117.6	61.6
Acquired and Covered Receivables
Certain Loans Acquired in Transfer Accounted for as Debt Securities Accretable Yield Movement Schedule [Line Items]
Accretion on acquired loans	$ 14.6	$ 16.3	$ 13.6