Basis of Presentation and Significant Accounting Policies (Details)		3 Months Ended
		Mar. 31, 2017 USD ($) Bank	Mar. 31, 2016 USD ($)	Dec. 31, 2016 USD ($)
Accounting Policies [Abstract]
Number of banks through which company operates (in bank) | Bank		1
Number of regional banking units Chemical Bank operates through (in bank) | Bank		7
Business Acquisition
Cumulative effect adjustment of change in accounting policy, net of tax impact	[1]			$ 3,659,000
Expense related to qualified affordable housing projects		$ 800,000	$ 600,000
Remaining investment in qualified affordable housing projects		31,800,000		29,500,000
Equity method investments		10,700,000		10,900,000
Remaining unfunded equity contributions		18,500,000		16,000,000
Impairment on tax credit projects		$ 0		0
Retained earnings
Business Acquisition
Cumulative effect adjustment of change in accounting policy, net of tax impact	[1]			$ 3,659,000

[1] Refer to Footnote 1, Basis of Presentation and Accounting Policies and Footnote 8, Loan Servicing Rights, for further details on this change in accounting policy election.