Pension plans and other postretirement benefits

9 Months Ended

Sep. 30, 2016

Compensation And Retirement Disclosure [Abstract]

Pension plans and other postretirement benefits

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 September 30
	2016			2015			2016			2015
	(in thousands)
Service cost	$	6,259			5,916			399		188
Interest cost on projected benefit obligation		20,853			17,754			1,242		651
Expected return on plan assets		(27,118	)		(23,527	)		—			—
Amortization of prior service credit		(807	)		(1,501	)		(339	)		(340	)
Amortization of net actuarial loss		7,536			11,207			15		26
Net periodic benefit cost	$	6,723			9,849			1,317		525

	Pension benefits						Other postretirement benefits
	Nine months ended September 30
	2016			2015			2016			2015
	(in thousands)
Service cost	$	18,778			17,748			1,197			562
Interest cost on projected benefit obligation		62,558			53,261			3,728			1,953
Expected return on plan assets		(81,355	)		(70,578	)		—			—
Amortization of prior service credit		(2,421	)		(4,504	)		(1,019	)		(1,019	)
Amortization of net actuarial loss		22,609			33,619			45			79
Net periodic benefit cost	$	20,169			29,546			3,951			1,575

Expense incurred in connection with the Company's defined contribution pension and retirement savings plans totaled $14,783,000 and $14,281,000 for the three months ended September 30, 2016 and 2015, respectively, and $47,747,000 and $44,377,000 for the nine months ended September 30, 2016 and 2015, respectively.