Employee Benefits (Tables)

12 Months Ended

Dec. 31, 2017

Retirement Benefits [Abstract]

Schedule of Projected Benefit Obligations, Fair Value of Plan Assets and Funded (Unfunded) Status

The following table presents the plans’ projected benefit obligations, fair value of plan assets and funded (unfunded) status:

(Dollars in thousands)	Qualified Pension Plan						Non-Qualified Retirement Plans
At December 31,	2017			2016			2017			2016
Change in Benefit Obligation:
Benefit obligation at beginning of period		$72,951			$67,550			$13,154			$13,015
Service cost	2,149			2,148			129			122
Interest cost	2,673			2,576			428			432
Actuarial loss	7,017			3,888			2,275			374
Benefits paid	(3,936		)	(3,072		)	(783		)	(789		)
Administrative expenses	(131		)	(139		)	—			—
Benefit obligation at end of period	80,723			72,951			15,203			13,154
Change in Plan Assets:
Fair value of plan assets at beginning of period	75,787			65,710			—			—
Actual return on plan assets	12,644			4,788			—			—
Employer contributions	3,000			8,500			783			789
Benefits paid	(3,936		)	(3,072		)	(783		)	(789		)
Administrative expenses	(131		)	(139		)	—			—
Fair value of plan assets at end of period	87,364			75,787			—			—
Funded (unfunded) status at end of period		$6,641			$2,836			($15,203	)		($13,154	)

Schedule of Components of Accumulated Other Comprehensive Income (Loss) Related to Retirements Plans

The following table presents components of accumulated other comprehensive income related to the qualified pension plan and non-qualified retirement plans, on a pre-tax basis:

(Dollars in thousands)	Qualified Pension Plan						Non-Qualified Retirement Plans
At December 31,	2017			2016			2017			2016
Net actuarial loss		$13,795			$15,593			$6,448			$4,519
Prior service credit	(39		)	(62		)	(1		)	(1		)
Total pre-tax amounts recognized in accumulated other comprehensive income		$13,756			$15,531			$6,447			$4,518

Schedule of Net Periodic Benefit Costs and Other Amounts Recognized in Other Comprehensive Income (Loss)

The following table presents components of net periodic benefit cost and other amounts recognized in other comprehensive income (loss), on a pre-tax basis:

(Dollars in thousands)	Qualified Pension Plan									Non-Qualified Retirement Plans
Years ended December 31,	2017			2016			2015			2017			2016			2015
Net Periodic Benefit Cost:
Service cost		$2,149			$2,148			$2,459			$129			$122			$78
Interest cost	2,673			2,576			2,928			428			432			490
Expected return on plan assets	(4,942		)	(4,633		)	(4,515		)	—			—			—
Amortization of prior service credit	(23		)	(23		)	(23		)	(1		)	(1		)	(1		)
Recognized net actuarial loss	1,114			828			1,249			347			247			245
Net periodic benefit cost	971			896			2,098			903			800			812
Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income (on a pre-tax basis):
Net (gain) loss	(1,798		)	2,904			(2,816		)	1,928			127			(156		)
Prior service cost	23			23			23			1			1			1
Recognized in other comprehensive (loss) income	(1,775		)	2,927			(2,793		)	1,929			128			(155		)
Total recognized in net periodic benefit cost and other comprehensive (loss) income		($804	)		$3,823			($695	)		$2,832			$928			$657

Schedule of Assumptions Used for Net Periodic Benefit Cost

The following table presents the measurement date and weighted-average assumptions used to determine benefit obligations at December 31, 2017 and 2016:

	Qualified Pension Plan		Non-Qualified Retirement Plans
	2017	2016	2017	2016
Measurement date	Dec 31, 2017	Dec 31, 2016	Dec 31, 2017	Dec 31, 2016
Discount rate	3.69%	4.18%	3.60%	4.00%
Rate of compensation increase	3.75	3.75	3.75	3.75

The following table presents the measurement date and weighted-average assumptions used to determine net periodic benefit cost for the years ended December 31, 2017, 2016 and 2015:

	Qualified Pension Plan			Non-Qualified Retirement Plans
	2017	2016	2015	2017	2016	2015
Measurement date	Dec 31, 2016	Dec 31, 2015	Dec 31, 2014	Dec 31, 2016	Dec 31, 2015	Dec 31, 2014
Discount rate	N/A	N/A	4.125%	N/A	N/A	3.90%
Equivalent single discount rate for benefit obligations	4.18%	4.48	N/A	4.00%	4.20	N/A
Equivalent single discount rate for service cost	4.29	4.63	N/A	4.25	4.59	N/A
Equivalent single discount rate for interest cost	3.73	3.88	N/A	3.40	3.44	N/A
Expected long-term return on plan assets	6.75	6.75	7.25	N/A	N/A	N/A
Rate of compensation increase	3.75	3.75	3.75	3.75	3.75	3.75

Schedule of Fair Value and Allocation of Plan Assets

The following table present the asset allocations of the qualified pension plan, by asset category:

December 31,	2017		2016
Asset Category:
Equity securities	65.7	%	63.8	%
Fixed income securities	30.0		32.4
Cash and cash equivalents	4.3		3.8
Total	100.0	%	100.0	%

The following tables present the fair values of the qualified pension plan’s assets:

(Dollars in thousands)
	Fair Value Measurements Using						Assets at Fair Value
December 31, 2017	Level 1		Level 2		Level 3
Assets:
Cash and cash equivalents		$3,760		$—		$—		$3,760
Obligations of U.S. government-sponsored enterprises	—		5,926		—		5,926
Obligations of states and political subdivisions	—		2,971		—		2,971
Corporate bonds	—		13,112		—		13,112
Common stocks	38,508		—		—		38,508
Mutual funds	23,087		—		—		23,087
Total plan assets		$65,355		$22,009		$—		$87,364

(Dollars in thousands)
	Fair Value Measurements Using						Assets at Fair Value
December 31, 2016	Level 1		Level 2		Level 3
Assets:
Cash and cash equivalents		$2,880		$—		$—		$2,880
Obligations of U.S. government-sponsored enterprises	—		4,233		—		4,233
Obligations of states and political subdivisions	—		3,418		—		3,418
Corporate bonds	—		13,775		—		13,775
Common stocks	33,893		—		—		33,893
Mutual funds	17,588		—		—		17,588
Total plan assets		$54,361		$21,426		$—		$75,787

Schedule of Expected Future Benefit Payments

The following table presents the benefit payments, which reflect expected future service, as appropriate, expected to be paid:

(Dollars in thousands)	Qualified Pension Plan		Non-Qualified Retirement Plans
2018		$3,964		$897
2019	2,931		891
2020	3,387		879
2021	3,784		868
2022	4,378		891
Years 2023 - 2027	28,050		4,221