Income Taxes (Summary of Loss Attributes, Section 382 Limitations, and Tax Expiration Periods) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Aug. 31, 2016
Operating Loss Carryforwards [Line Items]
Realized Built-in Losses	$ 77,292
Less amounts not recorded due to Sec 382 Limitation	(5,166)
Valuation Allowance	(1,150)
Federal
Operating Loss Carryforwards [Line Items]
Gross Federal Net Operating Losses	64,720
Gross Capital Losses
Operating Loss Carryforwards [Line Items]
Tax Credit Carryforwards	0
Business Tax Credits
Operating Loss Carryforwards [Line Items]
Tax Credit Carryforwards	3,514
Alternative Minimum Tax Credits - no expiration
Operating Loss Carryforwards [Line Items]
Tax Credit Carryforwards	25,829
Talmer
Operating Loss Carryforwards [Line Items]
Realized Built-in Losses		$ 88,700
Estimated recognized built in gain	253,200
Talmer | Federal
Operating Loss Carryforwards [Line Items]
Gross Federal Net Operating Losses		102,800
Tax Credit Carryforwards		1,000
Talmer | Alternative Minimum Tax Credits - no expiration
Operating Loss Carryforwards [Line Items]
Tax Credit Carryforwards		$ 14,900
Monarch
Operating Loss Carryforwards [Line Items]
Estimated recognized built in gain	2,800
Subject to limitations under section 382 | Talmer
Operating Loss Carryforwards [Line Items]
Annual Section 382 limitation-base	34,668
Realized Built-in Losses	0
Less amounts not recorded due to Sec 382 Limitation	0
Valuation Allowance	0
Subject to limitations under section 382 | Talmer | Federal
Operating Loss Carryforwards [Line Items]
Gross Federal Net Operating Losses	0
Subject to limitations under section 382 | Talmer | Gross Capital Losses
Operating Loss Carryforwards [Line Items]
Tax Credit Carryforwards	0
Subject to limitations under section 382 | Talmer | Business Tax Credits
Operating Loss Carryforwards [Line Items]
Tax Credit Carryforwards	170
Subject to limitations under section 382 | Talmer | Alternative Minimum Tax Credits - no expiration
Operating Loss Carryforwards [Line Items]
Tax Credit Carryforwards	12,473
Subject to limitations under section 382 | Monarch
Operating Loss Carryforwards [Line Items]
Annual Section 382 limitation-base	673
Realized Built-in Losses	0
Less amounts not recorded due to Sec 382 Limitation	(1,738)
Valuation Allowance	0
Subject to limitations under section 382 | Monarch | Federal
Operating Loss Carryforwards [Line Items]
Gross Federal Net Operating Losses	15,047
Subject to limitations under section 382 | Monarch | Gross Capital Losses
Operating Loss Carryforwards [Line Items]
Tax Credit Carryforwards	0
Subject to limitations under section 382 | Monarch | Business Tax Credits
Operating Loss Carryforwards [Line Items]
Tax Credit Carryforwards	1,651
Subject to limitations under section 382 | Monarch | Alternative Minimum Tax Credits - no expiration
Operating Loss Carryforwards [Line Items]
Tax Credit Carryforwards	106
Subject to limitations under section 382 | First Place Holdings/First Place Bank
Operating Loss Carryforwards [Line Items]
Annual Section 382 limitation-base	6,650
Realized Built-in Losses	68,356
Less amounts not recorded due to Sec 382 Limitation	(65)
Valuation Allowance	0
Subject to limitations under section 382 | First Place Holdings/First Place Bank | Federal
Operating Loss Carryforwards [Line Items]
Gross Federal Net Operating Losses	0
Subject to limitations under section 382 | First Place Holdings/First Place Bank | Gross Capital Losses
Operating Loss Carryforwards [Line Items]
Tax Credit Carryforwards	0
Subject to limitations under section 382 | First Place Holdings/First Place Bank | Business Tax Credits
Operating Loss Carryforwards [Line Items]
Tax Credit Carryforwards	781
Subject to limitations under section 382 | First Place Holdings/First Place Bank | Alternative Minimum Tax Credits - no expiration
Operating Loss Carryforwards [Line Items]
Tax Credit Carryforwards	2,115
Subject to limitations under section 382 | Talmer West Bank
Operating Loss Carryforwards [Line Items]
Annual Section 382 limitation-base	3,028
Realized Built-in Losses	8,936
Less amounts not recorded due to Sec 382 Limitation	(3,218)
Valuation Allowance	(585)
Subject to limitations under section 382 | Talmer West Bank | Federal
Operating Loss Carryforwards [Line Items]
Gross Federal Net Operating Losses	47,284
Subject to limitations under section 382 | Talmer West Bank | Gross Capital Losses
Operating Loss Carryforwards [Line Items]
Tax Credit Carryforwards	0
Subject to limitations under section 382 | Talmer West Bank | Business Tax Credits
Operating Loss Carryforwards [Line Items]
Tax Credit Carryforwards	0
Subject to limitations under section 382 | Talmer West Bank | Alternative Minimum Tax Credits - no expiration
Operating Loss Carryforwards [Line Items]
Tax Credit Carryforwards	0
Subject to limitations under section 382 | First of Huron Corp./Signature Bank
Operating Loss Carryforwards [Line Items]
Annual Section 382 limitation-base	365
Realized Built-in Losses	0
Less amounts not recorded due to Sec 382 Limitation	0
Valuation Allowance	0
Subject to limitations under section 382 | First of Huron Corp./Signature Bank | Federal
Operating Loss Carryforwards [Line Items]
Gross Federal Net Operating Losses	649
Subject to limitations under section 382 | First of Huron Corp./Signature Bank | Gross Capital Losses
Operating Loss Carryforwards [Line Items]
Tax Credit Carryforwards	0
Subject to limitations under section 382 | First of Huron Corp./Signature Bank | Business Tax Credits
Operating Loss Carryforwards [Line Items]
Tax Credit Carryforwards	0
Subject to limitations under section 382 | First of Huron Corp./Signature Bank | Alternative Minimum Tax Credits - no expiration
Operating Loss Carryforwards [Line Items]
Tax Credit Carryforwards	303
Subject to limitations under section 382 | From 2009 Ownership change
Operating Loss Carryforwards [Line Items]
Annual Section 382 limitation-base	145
Realized Built-in Losses	0
Less amounts not recorded due to Sec 382 Limitation	(145)
Valuation Allowance	0
Subject to limitations under section 382 | From 2009 Ownership change | Federal
Operating Loss Carryforwards [Line Items]
Gross Federal Net Operating Losses	1,740
Subject to limitations under section 382 | From 2009 Ownership change | Gross Capital Losses
Operating Loss Carryforwards [Line Items]
Tax Credit Carryforwards	0
Subject to limitations under section 382 | From 2009 Ownership change | Business Tax Credits
Operating Loss Carryforwards [Line Items]
Tax Credit Carryforwards	0
Subject to limitations under section 382 | From 2009 Ownership change | Alternative Minimum Tax Credits - no expiration
Operating Loss Carryforwards [Line Items]
Tax Credit Carryforwards	0
Not subject to limitations under section 382
Operating Loss Carryforwards [Line Items]
Realized Built-in Losses	0
Less amounts not recorded due to Sec 382 Limitation	0
Valuation Allowance	(565)
Not subject to limitations under section 382 | Federal
Operating Loss Carryforwards [Line Items]
Gross Federal Net Operating Losses	0
Not subject to limitations under section 382 | Gross Capital Losses
Operating Loss Carryforwards [Line Items]
Tax Credit Carryforwards	0
Not subject to limitations under section 382 | Business Tax Credits
Operating Loss Carryforwards [Line Items]
Tax Credit Carryforwards	912
Not subject to limitations under section 382 | Alternative Minimum Tax Credits - no expiration
Operating Loss Carryforwards [Line Items]
Tax Credit Carryforwards	$ 10,832