Retirement Plans (Tables)

12 Months Ended

Dec. 31, 2015

Compensation and Retirement Disclosure [Abstract]

Schedule of Changes in the Projected Benefit Obligation and Plan Assets of the Corporation’s Pension and Postretirement Plans

The following schedule sets forth the changes in the projected benefit obligation and plan assets of the Corporation's Pension and Postretirement Plans:

	Pension Plan						Postretirement Plan
	2015			2014			2015			2014
	(In thousands)
Projected benefit obligation:
Benefit obligation at beginning of year	$	129,160		$	105,914		$	3,702		$	3,477
Service cost	1,021			944			16			18
Interest cost	5,242			5,167			133			142
Net actuarial (gain) loss	(10,837		)	21,314			(363		)	312
Benefits paid	(4,713		)	(4,179		)	(241		)	(247		)
Benefit obligation at end of year	119,873			129,160			3,247			3,702
Fair value of plan assets:
Fair value of plan assets at beginning of year	130,775			128,829			—			—
Actual return on plan assets	868			6,125			—			—
Employer contributions	—			—			241			247
Benefits paid	(4,713		)	(4,179		)	(241		)	(247		)
Fair value of plan assets at end of year	126,930			130,775			—			—
Funded (unfunded) status at December 31	$	7,057		$	1,615		$	(3,247	)	$	(3,702	)
Accumulated benefit obligation	$	109,583		$	121,826		$	3,247		$	3,702

Schedule of Weighted-average rate assumptions of the Pension and Postretirement Plans

Weighted-average rate assumptions of the Pension and Postretirement Plans follow:

	Pension Plan						Postretirement Plan
	2015		2014		2013		2015		2014		2013
Discount rate used in determining benefit obligation — December 31	4.55	%	4.15	%	5.00	%	4.23	%	3.75	%	4.27	%
Discount rate used in determining expense	4.15		5.00		4.08		3.75		4.27		4.08
Expected long-term return on Pension Plan assets	6.75		7.00		7.00		—		—		—
Rate of compensation increase used in determining benefit obligation — December 31	3.50		3.50		3.50		—		—		—
Rate of compensation increase used in determining pension expense	3.50		3.50		3.50		—		—		—
Year 1 increase in cost of postretirement benefits	—		—		—		7.5		8.0		8.5

Schedule of Net periodic Pension Cost (Income) of the Pension and Postretirement Plans

Net periodic pension cost (income) of the Pension and Postretirement Plans was as follows for the years ended December 31:

	Pension Plan									Postretirement Plan
	2015			2014			2013			2015			2014			2013
	(In thousands)
Service cost	$	1,021		$	944		$	1,247		$	16		$	18		$	18
Interest cost	5,242			5,167			4,603			133			142			143
Expected return on plan assets	(8,645		)	(8,314		)	(7,794		)	—			—			—
Amortization of prior service credit	(5		)	(1		)	(1		)	130			130			343
Amortization of net actuarial loss (gain)	3,962			2,159			3,670			(1		)	(104		)	(73		)
Net cost (income)	$	1,575		$	(45	)	$	1,725		$	278		$	186		$	431

Schedule of Estimated Future Benefit Payments Under the Pension and Postretirement Plans

The following schedule presents estimated future benefit payments under the Pension and Postretirement Plans for retirees already receiving benefits and future retirees, assuming they retire and begin receiving unreduced benefits as soon as they are eligible:

	Pension Plan		Postretirement Plan
	(In thousands)
2016	$	5,223	$	272
2017	5,400		272
2018	5,730		268
2019	6,094		270
2020	6,272		268
2021 - 2025	35,771		1,254
Total	$	64,490	$	2,604

Schedule of Effect of One-Percentage-Point Change in Assumed Health Care Cost Trend Rates

A one percentage-point change in these rates would have the following effects:

	One Percentage-Point
	Increase		Decrease
	(In thousands)
Effect on total of service and interest cost components in 2015	$	13	$	(12	)
Effect on postretirement benefit obligation as of December 31, 2015	308		(269		)

Schedule of Allocation of Plan Assets

The Pension Plan's asset allocation by asset category was as follows:

	December 31,
Asset Category	2015		2014
Equity securities	68	%	68	%
Debt securities	31		30
Other	1		2
Total	100	%	100	%

The following schedule sets forth the fair value of the Pension Plan's assets and the level of the valuation inputs used to value those assets at December 31, 2015 and 2014:

Asset Category	Quoted Prices In Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
	(In thousands)
December 31, 2015
Cash	$	354	$	—	$	—	$	354
Equity securities:
U.S. large- and mid-cap stocks(a)	55,709		—		—		55,709
U.S. small-cap mutual funds	4,749		—		—		4,749
International large-cap mutual funds	14,124		—		—		14,124
Emerging markets mutual funds	4,886		—		—		4,886
Chemical Financial Corporation common stock	7,219		—		—		7,219
Debt securities:
U.S. Treasury and government sponsored agency bonds and notes	—		2,815		—		2,815
Corporate bonds(b)	—		3,554		—		3,554
Mutual funds(c)	33,424		—		—		33,424
Other	96		—		—		96
Total	$	120,561	$	6,369	$	—	$	126,930
December 31, 2014
Cash	$	2,594	$	—	$	—	$	2,594
Equity securities:
U.S. large- and mid-cap stocks(a)	56,718		—		—		56,718
U.S. small-cap mutual funds	5,409		—		—		5,409
International large-cap mutual funds	14,805		—		—		14,805
Emerging markets mutual funds	6,004		—		—		6,004
Chemical Financial Corporation common stock	6,455		—		—		6,455
Debt securities:
U.S. Treasury and government sponsored agency bonds and notes	998		2,043		—		3,041
Corporate bonds(b)	—		6,814		—		6,814
Mutual funds(c)	28,795		—		—		28,795
Other	140		—		—		140
Total	$	121,918	$	8,857	$	—	$	130,775

(a) Comprised of common stocks and mutual funds traded on U.S. Exchanges whose issuers had market capitalizations exceeding $3 billion.

(b) Comprised of investment grade bonds of U.S. issuers from diverse industries.

(c) Comprised primarily of fixed-income bonds issued by the U.S. Treasury and government sponsored agencies and bonds of U.S. and foreign issuers from diverse industries.

Schedule of Changes in Accumulated Other Comprehensive Income (Loss), Net of Tax, Related to the Corporation’s Pension, Postretirement and Supplemental Plans

The following sets forth the changes in accumulated other comprehensive income (loss), net of tax, related to the Corporation's Pension, Postretirement and Supplemental Plans during 2015:

	Pension Plan			Postretirement Plan		Supplemental Plan			Total
	(In thousands)
Accumulated other comprehensive income (loss) at beginning of year	$	(31,853	)	$	83	$	(473	)	$	(32,243	)
Comprehensive income (loss) adjustment:
Prior service costs (credits)	(3		)	84		—			81
Net actuarial loss	4,565			235		218			5,018
Comprehensive income (loss) adjustment	4,562			319		218			5,099
Accumulated other comprehensive income (loss) at end of year	$	(27,291	)	$	402	$	(255	)	$	(27,144	)

Schedule of Estimated Income (Loss) That Will Be Amortized From Accumulated Other Comprehensive Income (Loss) Into Net Periodic Cost

The estimated income (loss) that will be amortized from accumulated other comprehensive income (loss) into net periodic cost, net of tax, in 2016 is as follows:

	Pension Plan			Postretirement Plan			Supplemental Plan			Total
	(In thousands)
Prior service (costs) credits	$	—		$	(76	)	$	—		$	(76	)
Net gain (loss)	(1,468		)	65			(20		)	(1,423		)
Total	$	(1,468	)	$	(11	)	$	(20	)	$	(1,499	)