Retirement Plans (Tables)

12 Months Ended

Dec. 31, 2014

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
	2014			2013			2014			2013
	(In thousands)
Projected benefit obligation:
Benefit obligation at beginning of year	$	105,914		$	115,177		$	3,477		$	3,243
Service cost	944			1,247			18			18
Interest cost	5,167			4,603			142			143
Plan amendments	—			—			—			720
Net actuarial (gain) loss	21,314			(10,926		)	312			(428		)
Benefits paid	(4,179		)	(4,187		)	(247		)	(219		)
Benefit obligation at end of year	129,160			105,914			3,702			3,477
Fair value of plan assets:
Fair value of plan assets at beginning of year	128,829			98,187			—			—
Actual return on plan assets	6,125			19,829			—			—
Employer contributions	—			15,000			247			219
Benefits paid	(4,179		)	(4,187		)	(247		)	(219		)
Fair value of plan assets at end of year	130,775			128,829			—			—
Funded (unfunded) status at December 31	$	1,615		$	22,915		$	(3,702	)	$	(3,477	)
Accumulated benefit obligation	$	121,826		$	99,551		$	3,702		$	3,477

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
	2014		2013		2012		2014		2013		2012
Discount rate used in determining benefit obligation — December 31	4.15	%	5.00	%	4.08	%	3.75	%	4.27	%	4.08	%
Discount rate used in determining expense	5.00		4.08		4.90		4.27		4.08		4.90
Expected long-term return on Pension Plan assets	7.00		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	—		—		—		8.0		8.5		8.0

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
	2014			2013			2012			2014			2013			2012
	(In thousands)
Service cost	$	944		$	1,247		$	1,168		$	18		$	18		$	—
Interest cost	5,167			4,603			4,795			142			143			146
Expected return on plan assets	(8,314		)	(7,794		)	(6,925		)	—			—			—
Amortization of prior service credit	(1		)	(1		)	(1		)	130			343			(300		)
Amortization of net actuarial loss (gain)	2,159			3,670			2,382			(104		)	(73		)	(28		)
Net cost (income)	$	(45	)	$	1,725		$	1,419		$	186		$	431		$	(182	)

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)
2015	$	5,693	$	300
2016	6,402		310
2017	6,297		310
2018	6,241		310
2019	6,820		320
2020 - 2024	36,448		1,510
Total	$	67,901	$	3,060

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 2014	$	13	$	(12	)
Effect on postretirement benefit obligation as of December 31, 2014	327		(289		)

Schedule of Allocation of Plan Assets

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, 2014 and 2013:

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, 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
December 31, 2013
Cash	$	902	$	—	$	—	$	902
Equity securities:
U.S. large- and mid-cap stocks(a)	56,015		—		—		56,015
U.S. small-cap mutual funds	5,608		—		—		5,608
International large-cap mutual funds	15,504		—		—		15,504
Emerging markets mutual funds	6,360		—		—		6,360
Chemical Financial Corporation common stock	6,672		—		—		6,672
Debt securities:
U.S. Treasury and government sponsored agency bonds and notes	4,600		2,574		—		7,174
Corporate bonds(b)	—		8,693		—		8,693
Mutual funds(c)	21,901		—		—		21,901
Other	—		—		—		—
Total	$	117,562	$	11,267	$	—	$	128,829

(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.

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

	December 31,
Asset Category	2014		2013
Equity securities	68	%	70	%
Debt securities	30		29
Other	2		1
Total	100	%	100	%

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 2014:

	Pension Plan			Postretirement Plan			Supplemental Plan			Total
	(In thousands)
Accumulated other comprehensive income (loss) at beginning of year	$	(17,979	)	$	269		$	(330	)	$	(18,040	)
Comprehensive income (loss) adjustment:
Prior service costs (credits)	(1		)	84			—			83
Net actuarial loss	(13,873		)	(270		)	(143		)	(14,286		)
Comprehensive income (loss) adjustment	(13,874		)	(186		)	(143		)	(14,203		)
Accumulated other comprehensive income (loss) at end of year	$	(31,853	)	$	83		$	(473	)	$	(32,243	)

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 2015 is as follows:

	Pension Plan			Postretirement Plan			Supplemental Plan			Total
	(In thousands)
Prior service (costs) credits	$	3		$	(84	)	$	—		$	(81	)
Net gain (loss)	(2,576		)	1			(170		)	(2,745		)
Total	$	(2,573	)	$	(83	)	$	(170	)	$	(2,826	)