Components of Net Periodic Benefit Costs (Tables)

9 Months Ended

Sep. 30, 2020

Retirement Benefits [Abstract]

Schedule of Net Benefit Costs

Net periodic benefit (income) cost for Pension Plan, RIM Plan, Post-retirement Plan and split-dollar life insurance arrangement plan benefits for the three and nine months ended September 30, 2020 and 2019, includes the following components:

13.    Components of Net Periodic Benefit Cost (continued)

	For the Three Months Ended September 30,
	Pension Plan				RIM Plan				Post-retirement Plan				Split-Dollar Life Insurance
	2020		2019		2020		2019		2020		2019		2020		2019		Affected Line Item in the Consolidated Statements of Income
	(In thousands)
Service cost	$	2,032	$	1,746	$	67	$	53	$	99	$	84	$	120	$	88	Compensation and employee benefits
Interest cost	1,824		2,090		102		116		171		207		135		114		Other non-interest expense
Expected return on plan assets	(5,908)		(5,802)		—		—		—		—		—		—		Other non-interest expense
Amortization:
Prior service cost	—		—		—		—		—		—		14		14		Other non-interest expense
Net loss	1,492		770		99		61		77		37		113		62		Other non-interest expense
Net periodic (income) benefit cost	$	(560)	$	(1,196)	$	268	$	230	$	347	$	328	$	382	$	278

	For the Nine Months Ended September 30,
	Pension Plan				RIM Plan				Post-retirement Plan				Split-Dollar Life Insurance
	2020		2019		2020		2019		2020		2019		2020		2019		Affected Line Item in the Consolidated Statements of Income
	(In thousands)
Service cost	$	5,906	$	4,748	$	201	$	159	$	297	$	252	$	346	$	264	Compensation and employee benefits
Interest cost	5,887		6,478		306		348		513		621		384		342		Other non-interest expense
Expected return on plan assets	(17,383)		(15,256)		—		—		—		—		—		—		Other non-interest expense
Amortization:
Prior service cost	—		—		—		—		—		—		42		42		Other non-interest expense
Net loss	3,054		2,300		297		183		231		111		339		186		Other non-interest expense
Net periodic (income) benefit cost	$	(2,536)	$	(1,730)	$	804	$	690	$	1,041	$	984	$	1,111	$	834