Pension and Other Postretirement Benefit Plans (Textual) (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Multiemployer Plan, Period Contributions	$ 0.0
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Contribution to defined benefit pension plan	$ 0.0		$ 0.0
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate	4.55%
Chemical Financial Corporation [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of eligible pay contribution to certain employees	4.00%
Defined Contribution Plan, Employer Total Contribution Amount	$ 1.3	$ 1.1