Intangible Assets (Textual) (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	May. 31, 2015	Apr. 01, 2015	Dec. 31, 2014	Jun. 30, 2014
Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 285,512			$ 180,128	$ 120,164
Finite-Lived Intangible Assets, Remaining Amortization Period	10 years
Intangible Assets (Textual) [Abstract]
Impairment valuation allowance	$ 0			200	0
Core deposit intangible assets [Member]
Estimated Future Amortization Expense, Fiscal Year Maturity [Abstract]
2015	2,400
2016	4,300
2017	3,700
2018	3,500
2019	3,300
2020 and thereafter	11,200
Mortgage servicing rights [Member]
Intangible Assets (Textual) [Abstract]
Impairment valuation allowance	$ 0			$ 200	$ 0
Lake Michigan Financial Corp [Member]
Finite-Lived Intangible Assets [Line Items]
Goodwill		$ 100,002
Core deposit intangible assets acquired, business combination		$ 7,303
Monarch Community Bancorp [Member]
Finite-Lived Intangible Assets [Line Items]
Goodwill			$ 5,383
Core deposit intangible assets acquired, business combination			$ 1,930