7. Pension plans and other postretirement benefits

The Company provides defined benefit pension and other postretirement benefits (including health care and life insurance benefits) to qualified retired employees. Net periodic defined benefit cost for defined benefit plans consisted of the following:

	Pension Benefits						Other Postretirement Benefits
	Three Months Ended June 30
	2017			2016			2017			2016
	(In thousands)

Service cost	$	5,189			6,137			202		340
Interest cost on projected benefit obligation		19,943			20,822			778			1,281
Expected return on plan assets		(27,062	)		(26,423	)		—			—
Amortization of prior service cost (credit)		154			(789	)		(329	)		(330	)
Amortization of net actuarial loss (gain)		7,831			6,773			(469	)		30
Net periodic benefit cost	$	6,055			6,520			182			1,321

	Pension Benefits						Other Postretirement Benefits
	Six Months Ended June 30
	2017			2016			2017			2016
	(In thousands)

Service cost	$	10,097			12,519			585			798
Interest cost on projected benefit obligation		39,634			41,705			1,858			2,486
Expected return on plan assets		(54,262	)		(54,237	)		—			—
Amortization of prior service cost (credit)		279			(1,614	)		(679	)		(680	)
Amortization of net actuarial loss (gain)		14,631			15,073			(494	)		30
Net periodic benefit cost	$	10,379			13,446			1,270			2,634

Expense incurred in connection with the Company's defined contribution pension and retirement savings plans totaled $17,623,000 and $15,274,000 for the three months ended June 30, 2017 and 2016, respectively, and $37,042,000 and $32,964,000 for the six months ended June 30, 2017 and 2016, respectively.