Pension and Other Postretirement Benefit Plans (Textual) (Details) - USD ($)	1 Months Ended	3 Months Ended		8 Months Ended	9 Months Ended		12 Months Ended
	Sep. 30, 2016	Sep. 30, 2016	Sep. 30, 2015	Aug. 31, 2016	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Employer contributions to Pentegra DB Plan		$ 0	$ 0		$ 0
Chemical Financial Corporation [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of eligible pay contribution to certain employees (as a percent)					4.00%
Employer total contribution amount		$ 1,700,000	$ 1,400,000		$ 4,400,000	$ 3,800,000
Defined Benefit Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Contribution to defined benefit pension plan					$ 0		$ 0
Discount rate for pension plan expense (as a percent)	2.87%			4.55%
Increase in pension liability from remeasurement	$ 786,000
Non-Qualified Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Discount rate for pension plan expense (as a percent)				4.51%