Defined Benefit Pension Plans (Tables)

3 Months Ended

Mar. 31, 2016

Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [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 ended March 31,	2016			2015			2016		2015
Net Periodic Benefit Cost:
Service cost		$537			$615			$30		$20
Interest cost	644			732			108		122
Expected return on plan assets	(1,158		)	(1,129		)	—		—
Amortization of prior service (credit) cost	(6		)	(6		)	—		—
Recognized net actuarial loss	207			312			62		61
Net periodic benefit cost		$224			$524			$200		$203

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
Three months ended March 31,	2016	2015	2016	2015
Measurement date	Dec 31, 2015	Dec 31, 2014	Dec 31, 2015	Dec 31, 2014
Discount rate	N/A	4.125%	N/A	3.90%
Equivalent single discount rate for benefit obligations	4.48%	N/A	4.19%	N/A
Equivalent single discount rate for service cost	4.63	N/A	4.59	N/A
Equivalent single discount rate for interest cost	3.88	N/A	3.44	N/A
Expected long-term return on plan assets	6.75	7.25	N/A	N/A
Rate of compensation increase	3.75	3.75	3.75	3.75