Defined Benefit Pension Plans (Tables)

9 Months Ended

Sep. 30, 2018

Defined Benefit Plan [Abstract]

Components of Net Periodic Benefit Cost

The composition of net periodic benefit cost was as follows:

(Dollars in thousands)	Qualified Pension Plan												Non-Qualified Retirement Plans
	Three Months						Nine Months						Three Months				Nine Months
Periods ended September 30,	2018			2017			2018			2017			2018		2017		2018		2017
Net Periodic Benefit Cost:
Service cost (1)		$561			$537			$1,683			$1,611			$27		$32		$81		$97
Interest cost (2)	679			669			2,036			2,005			119		107		356		321
Expected return on plan assets (2)	(1,318		)	(1,236		)	(3,954		)	(3,707		)	—		—		—		—
Amortization of prior service (credit) cost (2)	(6		)	(6		)	(17		)	(17		)	—		—		—		—
Recognized net actuarial loss (2)	374			279			1,122			836			103		76		308		269
Net periodic benefit cost		$290			$243			$870			$728			$249		$215		$745		$687

(1) Included in salaries and employee benefits expense in the Unaudited Consolidated Statements of Income.

(2) Included in other expenses in the Unaudited Consolidated Statements of Income.

Schedule of Assumptions Used for Net Periodic Benefit Cost

The following table presents the measurement date and weighted-average assumptions used to determine net periodic benefit cost:

	Qualified Pension Plan		Non-Qualified Retirement Plans
For the nine months ended September 30,	2018	2017	2018	2017
Measurement date	Dec 31, 2017	Dec 31, 2016	Dec 31, 2017	Dec 31, 2016
Equivalent single discount rate for benefit obligations	3.69%	4.18%	3.58%	3.96%
Equivalent single discount rate for service cost	3.76	4.29	3.79	4.25
Equivalent single discount rate for interest cost	3.42	3.73	3.22	3.36
Expected long-term return on plan assets	6.75	6.75	N/A	N/A
Rate of compensation increase	3.75	3.75	3.75	3.75