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Employee Benefit Plans (Tables)

12 Months Ended

Dec. 31, 2021

Defined Benefit Plan Disclosure [Line Items]

Schedule of Allocation of Plan Assets

The percentages of total plan asset by investment category for our Pension Plan at December 31 were as follows:

			2021			2020
Equity			15%			21%
Real estate			7			3
Fixed income			74			69
Cash			1			3
Hedge funds			3			4
Total			100%			100%

Schedule of Employer Contribution to Employee Benefit Plans

Contributions for the years ended December 31 were as follows (in thousands):

			2021			2020
Defined Contribution Plan
Company retirement contributions			$	11,332		$	10,455
Company matching contributions			$	15,938		$	15,240

			2021			2020
Defined Benefit Plans
Defined Benefit Pension Plan			$	—		$	12,700
Non-Pension Defined Benefit Postretirement Healthcare Plan			$	6,432		$	6,058
Supplemental Non-Qualified Defined Benefit Plans			$	2,576		$	2,674

Schedule of Changes in Projected Benefit Obligations

The following tables provide a reconciliation of the employee benefit plan obligations and fair value of employee benefit plan assets, amounts recognized in the Consolidated Balance Sheets, accumulated benefit obligation, and reconciliation of components of the net periodic expense and elements of AOCI (in thousands):

Employee Benefit Plan Obligations

			Defined Benefit Pension Plan									Supplemental Non-qualified Defined Benefit Plans									Non-pension Defined Benefit Postretirement Healthcare Plan
As of December 31,			2021			2020						2021			2020						2021			2020
Change in benefit obligation:
Projected benefit obligation at beginning of year			$	514,008		$	485,376					$	55,054		$	54,088					$	70,238		$	65,277
Service cost (a)			5,038			5,411						3,149			1,579						2,237			2,056
Interest cost			9,313			13,426						706			1,099						1,058			1,649
Actuarial (gain) loss			(14,037)			47,064						(1,073)			962						(5,165)			5,804
Amendments			(561)			—						—			—						—			—
Benefits paid			(35,499)			(37,269)						(2,576)			(2,674)						(6,432)			(6,058)
Plan participants’ contributions			—			—						—			—						1,548			1,510
Projected benefit obligation at end of year			$	478,262		$	514,008					$	55,260		$	55,054					$	63,484		$	70,238

____________________

(a)    For the year ended December 31, 2020, Service Cost for the Supplemental Non-qualified Defined Benefit Plans includes a $1.4 million correction of a prior year overstatement of Projected benefit obligation.

Schedule of Changes in Fair Value of Plan Assets

			Defined Benefit Pension Plan									Supplemental Non-qualified Defined Benefit Plans									Non-pension Defined Benefit Postretirement Healthcare Plan (a)
As of December 31,			2021			2020						2021			2020						2021			2020
Change in fair value of plan assets:
Beginning fair value of plan assets			$	473,721		$	434,284					$	—		$	—					$	8,165		$	8,305
Investment income (loss)			20,165			64,006						—			—						(35)			33
Employer contributions			—			12,700						2,576			2,674						4,726			4,374
Retiree contributions			—			—						—			—						1,548			1,511
Benefits paid			(35,499)			(37,269)						(2,576)			(2,674)						(6,432)			(6,058)
Ending fair value of plan assets			$	458,387		$	473,721					$	—		$	—					$	7,972		$	8,165

____________________

(a)    Assets of VEBA trusts.

Schedule of Amounts Recognized in Balance Sheet

Amounts Recognized in the Consolidated Balance Sheets

			Defined Benefit Pension Plan									Supplemental Non-qualified Defined Benefit Plans									Non-pension Defined Benefit Postretirement Healthcare Plan
As of December 31,			2021			2020						2021			2020						2021			2020
Regulatory assets			$	67,403		$	86,677					$	—		$	—					$	11,660		$	16,102
Current liabilities			$	—		$	—					$	2,156		$	1,927					$	4,584		$	4,931
Non-current liabilities			$	19,872		$	40,287					$	53,104		$	53,127					$	50,949		$	57,142
Regulatory liabilities			$	3,830		$	3,607					$	—		$	—					$	2,447		$	2,140

Schedule of Accumulated and Projected Benefit Obligations

Accumulated Benefit Obligation

			Defined Benefit Pension Plan									Supplemental Non-qualified Defined Benefit Plans									Non-pension Defined Benefit Postretirement Healthcare Plan
As of December 31,			2021			2020						2021			2020						2021			2020
Accumulated Benefit Obligation			$	466,505		$	498,815					$	55,260		$	54,779					$	63,484		$	70,238

Components of Net Periodic Benefit Cost

			Defined Benefit Pension Plan												Supplemental Non-qualified Defined Benefit Plans												Non-pension Defined Benefit Postretirement Healthcare Plan
For the years ended December 31,			2021			2020			2019						2021			2020			2019						2021			2020			2019
Service cost (a)			$	5,038		$	5,411		$	5,383					$	3,149		$	1,579		$	4,995					$	2,237		$	2,056		$	1,815
Interest cost			9,313			13,426			17,374						706			1,099			1,295						1,058			1,649			2,247
Expected return on assets			(20,876)			(22,591)			(24,401)						—			—			—						(136)			(182)			(230)
Net amortization of prior service cost			—			—			26						—			2			2						(434)			(546)			(398)
Recognized net actuarial loss (gain)			7,315			8,372			3,763						1,754			1,702			535						466			20			—
Net periodic expense			$	790		$	4,618		$	2,145					$	5,609		$	4,382		$	6,827					$	3,191		$	2,997		$	3,434

____________________

(a)    For the year ended December 31, 2020, Service Cost for the Supplemental Non-qualified Defined Benefit Plans includes a $1.4 million correction of a prior year overstatement of Projected benefit obligation.

Schedule of Net Periodic Benefit Cost Not yet Recognized

			Defined Benefit Pension Plan									Supplemental Non-qualified Defined Benefit Plans									Non-pension Defined Benefit Postretirement Healthcare Plan
As of December 31,			2021			2020						2021			2020						2021			2020
Net (gain) loss			$	4,398		$	5,511					$	7,159		$	9,323					$	(308)		$	100
Prior service cost (gain)			(46)			—						—			—						(27)			(144)
Total amounts included in AOCI, after-tax not yet recognized as components of net periodic expense			$	4,352		$	5,511					$	7,159		$	9,323					$	(335)		$	(44)

Schedule of Assumptions Used

Assumptions

			Defined Benefit Pension Plan												Supplemental Non-qualified Defined Benefit Plans												Non-pension Defined Benefit Postretirement Healthcare Plan
Weighted-average assumptions used to determine benefit obligations:			2021			2020			2019						2021			2020			2019						2021			2020			2019
Discount rate			2.88		%	2.56		%	3.27		%				2.77		%	2.41		%	3.14		%				2.79		%	2.41		%	3.15		%
Rate of increase in compensation levels			3.08		%	3.34		%	3.49		%				5.00		%	5.00		%	5.00		%				N/A			N/A			N/A

			Defined Benefit Pension Plan												Supplemental Non-qualified Defined Benefit Plans												Non-pension Defined Benefit Postretirement Healthcare Plan
Weighted-average assumptions used to determine net periodic benefit cost for plan year:			2021			2020			2019						2021			2020			2019						2021			2020			2019
Discount rate (a)			2.56		%	3.27		%	4.40		%				2.41		%	3.14		%	4.34		%				2.41		%	3.15		%	4.28		%
Expected long-term rate of return on assets (b)			4.50		%	5.25		%	6.00		%				N/A			N/A			N/A						1.80		%	2.35		%	3.00		%
Rate of increase in compensation levels			3.34		%	3.49		%	3.52		%				5.00		%	5.00		%	5.00		%				N/A			N/A			N/A

____________________

(a)    The estimated discount rate for the Defined Benefit Pension Plan is 2.88% for the calculation of the 2022 net periodic pension costs.

(b)    The expected rate of return on plan assets is 4.25% for the calculation of the 2022 net periodic pension cost.

Schedule of Health Care Cost Trend Rates

The healthcare benefit obligation at December 31 was determined as follows:

			2021			2020
Trend Rate - Medical
Pre-65 for next year - All Plans			6.05%			6.10%
Pre-65 Ultimate trend rate - Black Hills Corp			4.50%			4.50%
Trend Year			2030			2027
Post-65 for next year - All Plans			5.10%			4.92%
Post-65 Ultimate trend rate - Black Hills Corp			4.50%			4.50%
Trend Year			2030			2029

Schedule of Expected Benefit Payments

The following benefit payments to employees, which reflect future service, are expected to be paid (in thousands):

			Defined Benefit Pension Plan						Supplemental Non-qualified Defined Benefit Plans						Non-pension Defined Benefit Postretirement Healthcare Plan
2022			$	26,249					$	2,156					$	5,806
2023			$	27,133					$	2,224					$	5,334
2024			$	27,683					$	2,410					$	5,042
2025			$	28,650					$	2,757					$	4,865
2026			$	28,968					$	2,782					$	4,752
2027-2031			$	144,422					$	12,553					$	21,615

Pension Plan

Defined Benefit Plan Disclosure [Line Items]

Schedule of Allocation of Plan Assets

The following tables set forth, by level within the fair value hierarchy, the assets that were accounted for at fair value on a recurring basis (in thousands):

Pension Plan			December 31, 2021
			Level 1						Level 2						Level 3						Total Investments Measured at Fair Value						NAV (a)						Total Investments
Common Collective Trust - Cash and Cash Equivalents			$	—					$	6,009					$	—					$	6,009					$	—					$	6,009
Common Collective Trust - Equity			—						70,262						—						70,262						—						70,262
Common Collective Trust - Fixed Income			—						339,219						—						339,219						—						339,219
Common Collective Trust - Real Estate			—						—						—						—						30,407						30,407
Hedge Funds			—						—						—						—						12,490						12,490
Total investments measured at fair value			$	—					$	415,490					$	—					$	415,490					$	42,897					$	458,387

Pension Plan			December 31, 2020
			Level 1						Level 2						Level 3						Total Investments Measured at Fair Value						NAV (a)						Total Investments
Common Collective Trust - Cash and Cash Equivalents			—						16,810						—						16,810						—						16,810
Common Collective Trust - Equity			—						100,311						—						100,311						—						100,311
Common Collective Trust - Fixed Income			—						324,845						—						324,845						—						324,845
Common Collective Trust - Real Estate			—						—						—						—						14,301						14,301
Hedge Funds			—						—						—						—						17,454						17,454
Total investments measured at fair value			$	—					$	441,966					$	—					$	441,966					$	31,755					$	473,721

____________________

(a)    Certain investments that are measured at fair value using NAV per share (or its equivalent) for practical expedient have not been classified in the fair value hierarchy. The fair value amounts presented in these tables for these investments are intended to permit reconciliation of the fair value hierarchy to the amounts presented in the reconciliation of changes in the plan’s benefit obligations and fair value of plan assets above.

Postretirement Health Coverage

Defined Benefit Plan Disclosure [Line Items]

Schedule of Allocation of Plan Assets

Non-pension Defined Benefit Postretirement Healthcare Plan			December 31, 2021
			Level 1						Level 2						Level 3						Total Investments Measured at Fair Value												Total Investments
Cash and Cash Equivalents			$	7,972					$	—					$	—					$	7,972											$	7,972
Total investments measured at fair value			$	7,972					$	—					$	—					$	7,972											$	7,972

Non-pension Defined Benefit Postretirement Healthcare Plan			December 31, 2020
			Level 1						Level 2						Level 3						Total Investments Measured at Fair Value												Total Investments
Cash and Cash Equivalents			$	8,165					$	—					$	—					$	8,165											$	8,165
Total investments measured at fair value			$	8,165					$	—					$	—					$	8,165											$	8,165

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