Postretirement benefits (Tables)

12 Months Ended

Dec. 31, 2016

Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]

Change in benefit obligation, plan assets and funded status

The following tables summarize the change in benefit obligation, plan assets and funded status during 2016 and 2015:

(in thousands)	Postretirement benefit plan			Pension plan
Change in benefit obligation:
Benefit obligation, December 31, 2014	$	100,432		$	3,864
Interest cost	3,309			128
Net actuarial loss (gain)	5,258			(130		)
Benefits paid from plan assets and company funds	(10,122		)	(324		)
Pharmacy rebates and Medicare Part D reimbursements	2,007			—
Benefit obligation, December 31, 2015	100,884			3,538
Interest cost	3,012			106
Net actuarial (gain) loss	(2,184		)	127
Benefits paid from plan assets and company funds	(7,524		)	(324		)
Benefit obligation, December 31, 2016	$	94,188		$	3,447
Change in plan assets:
Fair value of plan assets, December 31, 2014	$	124,675		$	—
Return on plan assets	391			—
Benefits paid	(7,932		)	—
Fair value of plan assets, December 31, 2015	117,134			—
Return on plan assets	7,717			—
Benefits paid	(6,723		)	—
Fair value of plan assets, December 31, 2016	$	118,128		$	—
Funded status, December 31, 2015	$	16,250		$	(3,538	)
Funded status, December 31, 2016	$	23,940		$	(3,447	)

Amounts recognized in consolidated balance sheets

The funded status of our plans was recognized in the consolidated balance sheets as of December 31 as follows:

	Postretirement benefit plan				Pension plan
(in thousands)	2016		2015		2016		2015
Other non-current assets	$	23,940	$	16,250	$	—	$	—
Accrued liabilities	—		—		324		324
Other non-current liabilities	—		—		3,123		3,214

Amounts included in other comprehensive loss that have not been recognized as components of postretirement benefit income

Amounts included in accumulated other comprehensive loss as of December 31 that have not been recognized as components of postretirement benefit income were as follows:

(in thousands)	2016			2015
Unrecognized prior service credit	$	17,021		$	18,442
Unrecognized net actuarial loss	(68,288		)	(74,524		)
Tax effect	15,583			17,260
Amount recognized in accumulated other comprehensive loss, net of tax	$	(35,684	)	$	(38,822	)

Amounts included in accumulated other comprehensive loss expected to be recognized in next 12 months

Amounts included in accumulated other comprehensive loss as of December 31, 2016 that we expect to recognize in postretirement benefit income during 2017 are as follows:

(in thousands)	Amounts expected to be recognized
Prior service credit	$	(1,421	)
Net actuarial loss	3,637
Total	$	2,216

Components of net periodic benefit income

Postretirement benefit income for the years ended December 31 consisted of the following components:

(in thousands)	2016			2015			2014
Interest cost	$	3,118		$	3,437		$	4,553
Expected return on plan assets	(7,335		)	(7,833		)	(8,734		)
Amortization of prior service credit	(1,421		)	(1,421		)	(1,421		)
Amortization of net actuarial losses	3,797			3,120			3,418
Net periodic benefit income	$	(1,841	)	$	(2,697	)	$	(2,184	)

Actuarial assumptions used in measuring benefit obligation and net periodic benefit income

In measuring benefit obligations as of December 31, the following discount rate assumptions were used:

	Postretirement benefit plan				Pension plan
	2016		2015		2016		2015
Discount rate	3.81	%	4.02	%	3.66	%	3.88	%

In measuring net periodic benefit income for the years ended December 31, the following assumptions were used:

	Postretirement benefit plan						Pension plan
	2016		2015		2014		2016		2015		2014
Discount rate	4.02	%	3.45	%	4.25	%	3.88	%	3.45	%	4.25	%
Expected return on plan assets	6.50	%	6.50	%	6.75	%	—		—		—

Health care cost trend rate assumptions

In measuring benefit obligations as of December 31 for our postretirement benefit plan, the following assumptions for health care cost trend rates were used:

	2016				2015				2014
	Participants under age 65		Participants age 65 and older		Participants under age 65		Participants age 65 and older		Participants under age 65		Participants age 65 and older
Health care cost trend rate assumed for next year	7.50	%	8.75	%	7.25	%	6.75	%	7.50	%	7.00	%
Rate to which the cost trend rate is assumed to decline (the ultimate trend rate)	4.50	%	4.50	%	5.00	%	5.00	%	5.00	%	5.00	%
Year that the rate reaches the ultimate trend rate	2025		2025		2026		2024		2021		2020

Effect of one-percentage-point change in assumed health care cost trend rates

Assumed health care cost trend rates have an effect on the amounts reported for health care plans. A one-percentage-point change in assumed health care cost trend rates would have the following effects:

(in thousands)	One percentage point increase		One percentage point decrease
Effect on total of service and interest cost	$	61	$	(57	)
Effect on benefit obligation	1,507		(1,413		)

Allocation of plan assets by asset category

The allocation of plan assets by asset category as of December 31 was as follows:

	Postretirement benefit plan
	2016		2015
U.S. large capitalization equity securities	33	%	33	%
International equity securities	18	%	18	%
Mortgage-backed securities	16	%	17	%
U.S. corporate debt securities	13	%	15	%
Government debt securities	13	%	10	%
U.S. small and mid-capitalization equity securities	7	%	7	%
Total	100	%	100	%

Our postretirement benefit plan has assets that are intended to meet long-term obligations. In order to meet these obligations, we employ a total return investment approach that considers cash flow needs and balances long-term projected returns against expected asset risk, as measured using projected standard deviations. Risk tolerance is established through consideration of projected plan liabilities, the plan's funded status, projected liquidity needs and current corporate financial condition.

The target asset allocation percentages for our postretirement benefit plan are based on our liability and asset projections. The targeted allocation of plan assets is 33% large capitalization equity securities, 42% fixed income securities, 18% international equity securities and 7% small and mid-capitalization equity securities.

Information regarding fair value measurements of plan assets was as follows:

	Fair value measurements using
	Quoted prices in active markets for identical assets		Significant other observable inputs		Significant unobservable inputs		Investments measured at net asset value		Fair value as of December 31, 2016
(in thousands)	(Level 1)		(Level 2)		(Level 3)
U.S. large capitalization equity securities	$	—	$	—	$	—	$	38,731	$	38,731
International equity securities	20,768		500		—		—		21,268
Mortgage-backed securities	—		15,542		—		3,245		18,787
U.S. corporate debt securities	—		14,753		—		802		15,555
Government debt securities	—		15,104		—		—		15,104
U.S. small and mid-capitalization equity securities	5,691		120		—		2,280		8,091
Other debt securities	—		592		—		—		592
Plan assets	$	26,459	$	46,611	$	—	$	45,058	$	118,128

	Fair value measurements using
	Quoted prices in active markets for identical assets		Significant other observable inputs		Significant unobservable inputs		Investments measured at net asset value		Fair value as of December 31, 2015
(in thousands)	(Level 1)		(Level 2)		(Level 3)
U.S. large capitalization equity securities	$	—	$	—	$	—	$	38,629	$	38,629
International equity securities	20,520		689		—		—		21,209
Mortgage-backed securities	—		15,716		—		4,441		20,157
U.S. corporate debt securities	—		16,285		—		689		16,974
Government debt securities	—		11,808		—		—		11,808
U.S. small and mid-capitalization equity securities	6,799		85		—		1,211		8,095
Other debt securities	149		113		—		—		262
Plan assets	$	27,468	$	44,696	$	—	$	44,970	$	117,134

Expected benefit payments

The following benefit payments are expected to be paid during the years indicated:

(in thousands)	Postretirement benefit plan		Pension plan
2017	$	9,037	$	320
2018	9,379		320
2019	9,166		310
2020	8,696		310
2021	8,210		300
2022 - 2026	33,410		1,390