Pension Plan and Postretirement Benefits Other Than Pension (Tables)

12 Months Ended

Dec. 31, 2016

Pension Plan and Postretirement Benefits Other Than Pension

Schedule of changes in net funded status, disclosure of amounts recognized in the balance sheet, and the assumptions used to determine the benefit obligation

					Other
	Pension Benefits				Postretirement Benefits
	2016		2015	2014	2016	2015	2014
	(in thousands)
Change in projected benefit obligation:
Net benefit obligation at beginning of year	$	210,783	208,085	172,105	8,421	9,902	8,172
Service cost		12,199	12,080	10,084	555	910	719
Interest cost		9,432	8,420	8,395	297	397	397
Benefits paid		(52,288)	(10,184)	(8,733)	(674)	(505)	(527)
Actuarial (gain) loss		795	(7,618)	26,410	1,790	(2,632)	760
Plan amendments		—	—	(176)	—	—	—
Retiree contributions		—	—	—	532	349	381
Curtailment gain		—	—	—	(8,475)	—	—
Net benefit obligation at end of year	$	180,921	210,783	208,085	2,446	8,421	9,902

Schedule of pension plan asset allocation

					Other
	Pension Benefits				Postretirement Benefits
	2016		2015	2014	2016	2015	2014
	(in thousands)
Change in plan assets:
Fair value of plan assets at beginning of year	$	173,885	175,548	170,430	—	—	—
Actual return on plan assets		2,932	(11,479)	(6,149)	—	—	—
Employer contributions		20,000	20,000	20,000	142	156	146
Retiree contributions		—	—	—	532	349	381
Benefits paid		(52,288)	(10,184)	(8,733)	(674)	(505)	(527)
Fair value of plan assets at end of year	$	144,529	173,885	175,548	—	—	—
Funded status at end of year	$	(36,392)	(36,898)	(32,537)	(2,446)	(8,421)	(9,902)

								Other
	Pension Benefits							Postretirement Benefits
	2016			2015		2014		2016		2015		2014
	(in thousands, except percentage data)
Amounts recognized in the statement of financial position:
Current liabilities	$	—		—		—		(458)		(316)		(279)
Noncurrent liabilities		(36,392)		(36,898)		(32,537)		(1,988)		(8,105)		(9,623)
Net amount recognized at end of year	$	(36,392)		(36,898)		(32,537)		(2,446)		(8,421)		(9,902)
Amounts not yet reflected in net periodic benefit cost and included in accumulated other comprehensive income:
Transition obligation	$	(11)		(16)		(21)		—		—		—
Prior service credit (cost)		(346)		(720)		(1,179)		6		2		(17)
Accumulated gain (loss)		(73,775)		(88,882)		(75,681)		954		2,897		265
Accumulated other comprehensive income (loss)		(74,132)		(89,618)		(76,881)		960		2,899		248
Cumulative employer contributions in excess of (less than) net periodic benefit cost		37,740		52,720		44,344		(3,406)		(11,320)		(10,150)
Net amount recognized at end of year	$	(36,392)		(36,898)		(32,537)		(2,446)		(8,421)		(9,902)
Weighted average assumptions used to determine benefit obligation at December 31:
Discount rate		4.39	%	4.60	%	4.13	%	3.46	%	4.44	%	4.07	%
Rate of compensation increase		5.12	%	5.12	%	5.12	%	Not applicable

Summary of entity's pension plan assets

	Percentage of		Percentage of
	Plan Assets at		Plan Assets at
Plan assets by category	December 31, 2016		December 31, 2015
Cash	18	%	24	%
Equity securities:
Domestic	49	%	53	%
International	17	%	15	%
Fixed income securities	10	%	5	%
Gold bullion	6	%	3	%
Total	100	%	100	%

Summary of entity's pension plan assets fair value

2016	Level 1		Level 2	Level 3	Total
	(in thousands)
Equity securities:
Domestic	$	71,159	—	—		71,159
International		24,622	—	—		24,622
Equity derivatives		—	12	—		12
Fixed income securities:
Mortgage-backed securities		—	10	—		10
U.S.treasuries		—	4,801	—		4,801
Corporate bond		—	526	—		526
Foreign Bonds		—	8,897	—		8,897
Gold bullion		8,420	—	—		8,420
Total investment securities		104,201	14,246	—		118,447
Cash and other						26,082
Total					$	144,529

2015	Level 1		Level 2	Level 3	Total
	(in thousands)
Equity securities:
Domestic	$	92,037	—	—		92,037
International		25,822	—	—		25,822
Equity derivatives		—	280	—		280
Fixed income securities:
Mortgage-backed securities		—	11	—		11
U.S.treasuries		—	8,113	—		8,113
Gold bullion		5,226	—	—		5,226
Total investment securities		123,085	8,404	—		131,489
Cash and other						42,396
Total					$	173,885

Summary of the activity of plan assets categorized as Level 3

	2016		2015
	(in thousands)
Level 3 plan assets at beginning of year	$	—	3,402
Sales		—	(3,432)
Valuation change		—	30
Level 3 plan assets at end of year	$	—	—

Schedule of components of net periodic pension and other postretirement costs

					Other
	Pension Benefits				Postretirement Benefits
	2016		2015	2014	2016	2015	2014
	(in thousands)
Components of net periodic benefit cost:
Service cost	$	12,199	12,080	10,084	555	910	719
Interest cost		9,432	8,420	8,395	297	397	397
Expected return on plan assets		(13,927)	(14,510)	(14,016)	—	—	—
Actuarial (gain) loss amortization		6,215	5,171	1,496	(153)	—	(17)
Prior service cost amortization		374	459	468	4	19	55
Transition obligation amortization		5	5	5	—	—	—
Settlement loss		20,681	—	—	—	—	—
Curtailment gain		—	—	—	(8,475)	—	—
Total (1)	$	34,979	11,625	6,432	(7,772)	1,326	1,154

Schedule of weighted average assumptions used to determine net periodic cost and benefit obligation

							Other
	Pension Benefits						Postretirement Benefits
	2016		2015		2014		2016		2015		2014
Discount rate	4.60	%	4.13	%	4.97	%	4.44	%	4.07	%	4.94	%
Expected return on plan assets	7.50	%	7.75	%	7.75	%	Not applicable
Rate of compensation increase	5.12	%	5.12	%	5.12	%	Not applicable

Schedule of expected benefit payments to be paid

			Other
	Pension		Postretirement
	Benefits		Benefits
	(in thousands)
2017	$	5,492	458
2018		7,066	416
2019		7,496	404
2020		8,240	319
2021		10,613	237
2022 through 2026		63,588	559
	$	102,495	2,393