Business Combinations Reconciliation of Carrying Amount of Acquired Loans (Details) (Acquired Impaired Loans, USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Jun. 30, 2014 Citizens Republic Bancorp	Apr. 12, 2013 Citizens Republic Bancorp
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Outstanding Balance								$ 1,231,172
Certain Loans Acquired in Transfer, Nonaccretable Difference								279,899
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Acquired During Period, Cash Flows Expected to be Collected at Acquisition								951,273
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield	137,442	142,284	136,646	120,067	0	0	0	131,558
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Carrying Amount, Net	$ 519,250	$ 557,199	$ 601,000	$ 752,682	$ 0	$ 0	$ 0	$ 819,715