Retirement Plans (Tables)

12 Months Ended

Dec. 31, 2019

Defined Benefit Plan Disclosure [Line Items]

Asset Allocation

As of December 31, 2019 and 2018, these assets were allocated among asset categories as follows:

Asset Category	2019			2018			Current Minimum, Target and Maximum Allocation Policy
U.S. equity securities		53	%		52	%		30% — 50%— 70	%
International equity securities		19			17			0% — 20%— 30	%
Debt securities		26			28			15% — 30%— 55	%
Cash and cash equivalents		2			3			0% — 0%— 5	%
		100	%		100	%

Change in Benefit Obligation

The following table presents the change in benefit obligation and plan assets for the Company’s defined benefit plans and postretirement benefit plan (in thousands):

													Other Postretirement Benefits
	Pension Benefits												Postretirement Welfare Plan
	Pension Plan						SERP
	2019			2018			2019			2018			2019			2018
Change in benefit obligation
Benefit obligation at beginning of year	$	381,483		$	354,994		$	1,246		$	1,412		$	743		$	679
Service cost		7,364			7,622			—			—			—			—
Interest cost		16,493			15,499			52			49			31			24
Actuarial loss (gain)		49,478			(44,935	)		72			(70	)		(22	)		143
Gross benefits paid		(11,957	)		(11,749	)		(145	)		(145	)		(90	)		(103	)
Curtailments		—			(3,081	)		—			—			—			—
Acquisition		—			63,133			—			—			—			—
Benefit obligation at end of year	$	442,861		$	381,483		$	1,225		$	1,246		$	662		$	743
Accumulated benefit obligation at end of year	$	417,981		$	356,797		$	1,225		$	1,246		$	662		$	743

Weighted-Average Assumption Used to Determine Benefit Obligation and Net Periodic Benefit Cost

Weighted-average assumption used to determine benefit obligation at end of year
Discount rate (a)		3.5	%		4.4	%	3.5	%	4.4	%	3.5	%	4.4	%
Rate of compensation increase	Service-based table			Service-based table			—		—		—		—
Health care cost trend rate
Initial rate		—			—		—		—		6.75	%	7.0	%
Ultimate rate		—			—		—		—		5.0	%	5.0	%
Years to ultimate		—			—		—		—		2025		2025

(a)          The discount rate for the Higman pension plan in 2018 was changed from 4.13% as of February 14, 2018 and 4.02% as of March 31, 2018 to 4.40% as of December 31, 2018.

Effect of One-Percentage-Point Change in Assumed Health Care Cost Trend Rate

Effect of one-percentage-point change in assumed health care cost trend rate on postretirement obligation
Increase	$	—	$	—	$	—	$	—	$	68		$	75
Decrease		—		—		—		—		(59	)		(65	)

Change in Plan Assets

Change in plan assets
Fair value of plan assets at beginning of year	$	303,151		$	294,995		$	—		$	—		$	—		$	—
Actual return on plan assets		63,939			(18,214	)		—			—			—			—
Employer contribution		3,064			8,102			145			145			90			103
Gross benefits paid		(11,957	)		(11,749	)		(145	)		(145	)		(90	)		(103	)
Acquisition		—			30,017			—			—			—			—
Fair value of plan assets at end of year	$	358,197		$	303,151		$	—		$	—		$	—		$	—

Funded Status at End of Year

													Other Postretirement Benefits
	Pension Benefits												Postretirement Welfare Plan
	Pension Plan						SERP
	2019			2018			2019			2018			2019			2018
Funded status at end of year
Fair value of plan assets	$	358,197		$	303,151		$	—		$	—		$	—		$	—
Benefit obligations		(442,861	)		(381,483	)		(1,225	)		(1,246	)		(662	)		(743	)
Funded status and amount recognized at end of year	$	(84,664	)	$	(78,332	)	$	(1,225	)	$	(1,246	)	$	(662	)	$	(743	)

Amounts Recognized in the Consolidated Balance Sheets

Amounts recognized in the consolidated balance sheets
Noncurrent asset	$	—		$	—		$	—		$	—		$	—		$	—
Current liability		—			—			(159	)		(158	)		(60	)		(65	)
Long-term liability		(84,664	)		(78,332	)		(1,066	)		(1,087	)		(602	)		(678	)

Amounts Recognized in Accumulated Other Comprehensive Income

Amounts recognized in accumulated other comprehensive income
Net actuarial loss (gain)	$	52,160	$	47,101	$	460	$	415	$	(3,795	)	$	(4,313	)
Prior service cost (credit)		—		—		—		—		—			—
Accumulated other compensation income	$	52,160	$	47,101	$	460	$	415	$	(3,795	)	$	(4,313	)

Projected Benefit Obligation in Excess of Plan Assets

The projected benefit obligation and fair value of plan assets for pension plans with a projected benefit obligation in excess of plan assets at December 31, 2019 and 2018 were as follows (in thousands):

	Pension Benefits
	Pension Plan				SERP
	2019		2018		2019		2018
Projected benefit obligation in excess of plan assets
Projected benefit obligation at end of year	$	442,861	$	381,483	$	1,225	$	1,246
Fair value of plan assets at end of year		358,197		303,151		—		—

Accumulated Benefit Obligation in Excess of Plan Assets

The projected benefit obligation, accumulated benefit obligation and fair value of plan assets for pension plans with an accumulated benefit obligation in excess of plan assets at December 31, 2019 and 2018 were as follows (in thousands):

	Pension Benefits
	Pension Plan				SERP
	2019		2018		2019		2018
Accumulated benefit obligation in excess of plan assets
Projected benefit obligation at end of year	$	442,861	$	381,483	$	1,225	$	1,246
Accumulated benefit obligation at end of year		417,981		356,797		1,225		1,246
Fair value of plan assets at end of year		358,197		303,151		—		—

Employer Contribution

									Other Postretirement Benefits
	Pension Benefits								Postretirement Welfare Plan
	Pension Plan				SERP
	2019		2018		2019		2018		2019		2018
Expected employer contributions
First year	$	2,407	$	2,395	$	—	$	—	$	—	$	—

Expected Benefit Payments

									Other Postretirement Benefits
	Pension Benefits								Postretirement Welfare Plan
	Pension Plan				SERP
	2019		2018		2019		2018		2019		2018
Expected benefit payments (gross)
Year one	$	12,063	$	12,209	$	162	$	162	$	61	$	66
Year two		13,123		13,108		158		159		62		68
Year three		14,300		13,959		133		155		51		69
Year four		15,572		14,959		107		130		51		57
Year five		16,857		16,052		103		104		49		56
Next five years		100,587		96,547		426		447		220		261

Pension Benefits [Member]

Defined Benefit Plan Disclosure [Line Items]

Net Periodic Benefit Cost

	Pension Benefits
	Pension Plan									SERP
	2019			2018			2017			2019			2018			2017
Components of net periodic benefit cost
Service cost	$	7,364		$	7,622		$	10,677		$	—		$	—		$	—
Interest cost		16,493			15,499			13,729			52			49			58
Expected return on plan assets		(20,956	)		(22,406	)		(18,195	)		—			—			—
Amortization:
Actuarial loss		1,438			2,890			4,400			28			23			28
Prior service credit		—			—			—			—			—			—
Net periodic benefit cost		4,339			3,605			10,611			80			72			86
Other changes in plan assets and benefit obligations recognized in other comprehensive income
Current year actuarial loss (gain)		6,497			(7,396	)		7,562			73			(70	)		42
Recognition of actuarial loss		(1,438	)		(2,890	)		(37,833	)		(28	)		(23	)		(28	)
Recognition of prior service credit		—			—			—			—			—			—
Total recognized in other comprehensive income		5,059			(10,286	)		(30,271	)		45			(93	)		14
Total recognized in net periodic benefit cost and other comprehensive income	$	9,398		$	(6,681	)	$	(19,660	)	$	125		$	(21	)	$	100
Weighted average assumptions used to determine net periodic benefit cost
Discount rate (a)		4.4	%		3.7	%		4.2/4.0	%		4.4	%		3.7	%		4.2	%
Expected long-term rate of return on plan assets		7.0	%		7.0	%		7.0	%		—			—			—
Rate of compensation increase	Service- based table			Service- based table			Service- based table				—			—			—

(a) The 2018 discount rate for benefit cost for the Higman pension plan was changed from 4.13% as of February 14, 2018 and 4.02% as of March 31, 2018 to 4.40% as of December 31, 2018.  In 2017, benefit cost for the pension plan was determined using a discount rate of 4.2% for the period beginning January 1, 2017 and ending April 11, 2017 and 4.0% for the period beginning April 12, 2017 and ending December 31, 2017.

Estimated Amounts that will be Amortized from Accumulated Other Comprehensive Income into Net Periodic Benefit Cost

The estimated amounts that will be amortized from accumulated other comprehensive income into net periodic benefit cost in 2020 are as follows (in thousands):

	Pension Benefits
	Pension Plan		SERP
Actuarial loss	$	929	$	35
Prior service credit		—		—
	$	929	$	35

Other Postretirement Benefits [Member]

Defined Benefit Plan Disclosure [Line Items]

Net Periodic Benefit Cost

	Other Postretirement Benefits
	Postretirement Welfare Plan
	2019			2018			2017
Components of net periodic benefit cost
Service cost	$	—		$	—		$	—
Interest cost		31			24			27
Amortization:
Actuarial gain		(540	)		(596	)		(668	)
Prior service cost		—			—			—
Net periodic benefit cost		(509	)		(572	)		(641	)
Other changes in benefit obligations recognized in other comprehensive income
Current year actuarial loss (gain)		(22	)		144			52
Recognition of actuarial gain		540			596			668
Recognition of prior service cost		—			—			—
Total recognized in other comprehensive income		518			740			720
Total recognized in net periodic benefit cost and other comprehensive income	$	9		$	168		$	79
Weighted average assumptions used to determine net periodic benefit cost
Discount rate		4.4	%		3.7	%		4.2	%
Health care cost trend rate:
Initial rate		7.0	%		7.0	%		7.0	%
Ultimate rate		5.0	%		5.0	%		5.0	%
Years to ultimate		2025			2022			2021
Effect of one-percentage-point change in assumed health care cost trend rate on aggregate service and interest cost
Increase	$	3		$	3		$	3
Decrease		(3	)		(2	)		(3	)

Estimated Amounts that will be Amortized from Accumulated Other Comprehensive Income into Net Periodic Benefit Cost

The estimated amounts that will be amortized from accumulated other comprehensive income into net periodic benefit cost in 2020 are as follows (in thousands):

	Other Postretirement Benefits
	Postretirement Welfare Plan
Actuarial gain	$	(522	)
Prior service cost		—
	$	(522	)