We sponsor a defined contribution plan in which we match our employees’ qualifying contributions, resulting in additional expense to us. Expenses related to the defined contribution plan were $2.4 million for each of the three months ended June 30, 2019 and 2020, respectively, and $6.5 million and $6.9 million for the six months ended June 30, 2019 and 2020, respectively.

In addition, we sponsor two pension plans, including one for all non-union employees and one that covers certain union employees, and a postretirement benefit plan for certain employees. Prior to the March 2020 sale of our New Haven terminal (See Note 1 – Organization, Description of Business and Basis of Presentation), we sponsored an additional union pension plan that covered union employees at that terminal. Net periodic benefit expense for the three and six months ended June 30, 2019 and 2020 was as follows (in thousands):



	Three Months Ended					Three Months Ended
	June 30, 2019					June 30, 2020
	Pension Benefits			Other Postretirement Benefits		Pension Benefits			Other Postretirement Benefits
Components of net periodic benefit costs:
Service cost	$	6,358		$	43	$	6,735		$	67
Interest cost	3,110			135		2,711			127
Expected return on plan assets	(2,317		)	—		(2,809		)	—
Amortization of prior service credit	(45		)	—		(45		)	—
Amortization of actuarial loss	1,508			117		1,322			136
Settlement cost	2,060			—		—			—
Net periodic benefit cost	$	10,674		$	295	$	7,914		$	330



	Six Months Ended					Six Months Ended
	June 30, 2019					June 30, 2020
	Pension Benefits			Other Postretirement Benefits		Pension Benefits			Other Postretirement Benefits
Components of net periodic benefit costs:
Service cost	$	12,885		$	97	$	13,938		$	129
Interest cost	6,110			254		5,513			239
Expected return on plan assets	(4,691		)	—		(5,695		)	—
Amortization of prior service credit	(90		)	—		(90		)	—
Amortization of actuarial loss	2,785			188		2,734			255
Settlement cost	2,060			—		969			—
Settlement gain on disposition of assets	—			—		(1,342		)	—
Net periodic benefit cost	$	19,059		$	539	$	16,027		$	623

The service component of our net periodic benefit costs is presented in operating expense and G&A expense, and the non-service components are presented in other (income) expense in our consolidated statements of income.

The changes in accumulated other comprehensive loss (“AOCL”) related to employee benefit plan assets and benefit obligations for the three and six months ended June 30, 2019 and 2020 were as follows (in thousands):



	Three Months Ended						Three Months Ended
	June 30, 2019						June 30, 2020
Gains (Losses) Included in AOCL	Pension Benefits			Other Postretirement Benefits			Pension Benefits			Other Postretirement Benefits
Beginning balance	$	(87,370	)	$	(5,338	)	$	(101,447	)	$	(8,259	)
Net actuarial gain (loss)	(10,029		)	(884		)	1,560			(1,146		)
Recognition of prior service credit amortization in income	(45		)	—			(45		)	—
Recognition of actuarial loss amortization in income	1,508			117			1,322			136
Recognition of settlement cost in income	2,060			—			—			—
Ending balance	$	(93,876	)	$	(6,105	)	$	(98,610	)	$	(9,269	)



	Six Months Ended						Six Months Ended
	June 30, 2019						June 30, 2020
Gains (Losses) Included in AOCL	Pension Benefits			Other Postretirement Benefits			Pension Benefits			Other Postretirement Benefits
Beginning balance	$	(88,602	)	$	(5,409	)	$	(104,739	)	$	(8,378	)
Net actuarial gain (loss)	(10,029		)	(884		)	813			(1,146		)
Curtailment gain	—			—			1,703			—
Recognition of prior service credit amortization in income	(90		)	—			(90		)	—
Recognition of actuarial loss amortization in income	2,785			188			2,734			255
Recognition of settlement cost in income	2,060			—			969			—
Ending balance	$	(93,876	)	$	(6,105	)	$	(98,610	)	$	(9,269	)

Contributions estimated to be paid into the plans in 2020 are $29.3 million and $0.7 million for the pension plans and other postretirement benefit plan, respectively.