Fair value measurements

6 Months Ended

Jun. 30, 2024

Fair Value Disclosures [Abstract]

Fair value measurements

Fair value measurements

Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability (an exit price) in an orderly transaction between market participants at the measurement date. The fair value ASC establishes a hierarchy for grouping assets and liabilities, based on the significance of inputs. The estimated fair values of the Company's assets and liabilities measured on a recurring basis are determined using the market approach.

The Company measures its investments in certain fixed-income and equity securities at fair value with changes in fair value recognized in income. The Company anticipates using these investments, which consist of insurance contracts, to satisfy its obligations under its unfunded, nonqualified defined benefit and defined contribution plans for executive officers and certain key management employees and invests in these fixed-income and equity securities for the purpose of earning investment returns and capital appreciation. These investments, which totaled $61.0 million, $84.1 million and $66.2 million, at June 30, 2024 and 2023, and December 31, 2023, respectively, are classified as Investments on the Consolidated Balance Sheets. The net unrealized gain on these investments was $362,000 and $3.2 million for the three and six months ended June 30, 2024, respectively. The net unrealized gain on these investments was $1.9 million and $4.9 million for the three and six months ended June 30, 2023, respectively. The change in fair value, which is considered part of the cost of the plan, is classified in Other income on the Consolidated Statements of Income. In the first quarter of 2024 and the fourth quarter of 2023 the Company withdrew $9.0 million and $20.0 million, respectively, of its cost basis, which reduced Investments on the Consolidated Balance Sheets.

The Company did not elect the fair value option, which records gains and losses in income, for its available-for-sale securities, which include mortgage-backed securities and U.S. Treasury securities. These available-for-sale securities are recorded at fair value and are classified as Investments on the Consolidated Balance Sheets. Unrealized gains or losses are recorded in Accumulated other comprehensive loss on the Consolidated Balance Sheets. Details of available-for-sale securities were as follows:

June 30, 2024	Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
	(In thousands)
Mortgage-backed securities	$	8,091	$	3	$	482	$	7,612
U.S. Treasury securities	3,806		54		—		3,860
Total	$	11,897	$	57	$	482	$	11,472

June 30, 2023	Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
	(In thousands)
Mortgage-backed securities	$	8,542	$	—	$	651	$	7,891
U.S. Treasury securities	3,091		5		46		3,050
Total	$	11,633	$	5	$	697	$	10,941

December 31, 2023	Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
	(In thousands)
Mortgage-backed securities	$	8,234	$	17	$	470	$	7,781
U.S. Treasury securities	3,521		28		8		3,541
Total	$	11,755	$	45	$	478	$	11,322

On May 31, 2023, the Company completed the Knife River separation and retained approximately 10 percent, or 5.7 million shares of Knife River common stock immediately following the separation, which were disposed of in a tax-free exchange in November 2023. The Company did not retain a controlling interest in Knife River and therefore the fair value of its retained shares and subsequent fair value changes are included in assets of and results from continuing operations, respectively. At June 30, 2023, the fair value of the Company's retained shares in Knife River common stock of $246.1 million was reflected in Retained shares in Knife River on the Consolidated Balance Sheet and was remeasured at fair value based on Knife River's closing stock price on June 30, 2023, with an unrealized gain of $140.0 million recorded in Unrealized gain on retained shares in Knife River on the Consolidated Statements of Income.

The Company's assets measured at fair value on a recurring basis were as follows:

	Fair Value Measurements at June 30, 2024, Using
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Balance at June 30, 2024
	(In thousands)
Assets:
Money market funds	$	—	$	10,904	$	—	$	10,904
Insurance contracts*	—		60,952		—		60,952
Available-for-sale securities:
Mortgage-backed securities	—		7,612		—		7,612
U.S. Treasury securities	—		3,860		—		3,860
Total assets measured at fair value	$	—	$	83,328	$	—	$	83,328

* The insurance contracts invest approximately 55 percent in fixed-income investments, 19 percent in common stock of large-cap companies, 10 percent in target date investments, 8 percent in common stock of mid-cap companies, 4 percent in common stock of small-cap companies, 3 percent in cash equivalents, and 1 percent in international investments.

	Fair Value Measurements at June 30, 2023, Using
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Balance at June 30, 2023
	(In thousands)
Assets:
Retained shares in Knife River	$	246,063	$	—	$	—	$	246,063
Money market funds	—		5,737		—		5,737
Insurance contracts*	—		84,099		—		84,099
Available-for-sale securities:
Mortgage-backed securities	—		7,891		—		7,891
U.S. Treasury securities	—		3,050		—		3,050
Total assets measured at fair value	$	246,063	$	100,777	$	—	$	346,840

* The insurance contracts invest approximately 67 percent in fixed-income investments, 14 percent in common stock of large-cap companies, 7 percent in common stock of mid-cap companies, 6 percent in common stock of small-cap companies, 4 percent in target date investments and 2 percent in cash equivalents.

	Fair Value Measurements at December 31, 2023, Using
	Quoted Prices in Active Markets for Identical Assets  (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs  (Level 3)		Balance at December 31, 2023
	(In thousands)
Assets:
Money market funds	$	—	$	6,409	$	—	$	6,409
Insurance contracts*	—		66,283		—		66,283
Available-for-sale securities:
Mortgage-backed securities	—		7,781		—		7,781
U.S. Treasury securities	—		3,541		—		3,541
Total assets measured at fair value	$	—	$	84,014	$	—	$	84,014

* The insurance contracts invest approximately 60 percent in fixed-income investments, 15 percent in common stock of large-cap companies, 8 percent in target date investments, 7 percent in common stock of mid-cap companies, 5 percent in common stock of small-cap companies, 3 percent in cash equivalents, 1 percent in high yield investments and 1 percent in international investments.

The Company's money market funds are valued at the net asset value of shares held at the end of the period, based on published market quotations on active markets, or using other known sources including pricing from outside sources. The estimated fair value of the Company's mortgage-backed securities and U.S. Treasury securities are based on comparable market transactions, other observable inputs or other sources, including pricing from outside sources. The estimated fair value of the Company's insurance contracts are based on contractual cash surrender values that are determined primarily by investments in managed separate accounts of the insurer. These amounts approximate fair value. The managed separate accounts are valued based on other observable inputs or corroborated market data.

Though the Company believes the methods used to estimate fair value are consistent with those used by other market participants, the use of other methods or assumptions could result in a different estimate of fair value.

The Company applies the provisions of the fair value measurement standard to its nonrecurring, non-financial measurements, including long-lived asset impairments. These assets are not measured at fair value on an ongoing basis but are subject to fair value adjustments only in certain circumstances. The Company reviews the carrying value of its long-lived assets, excluding goodwill, whenever events or changes in circumstances indicate that such carrying amounts may not be recoverable.

The Company's long-term debt is not measured at fair value on the Consolidated Balance Sheets and the fair value is being provided for disclosure purposes only. The fair value was categorized as Level 2 in the fair value hierarchy and was based on discounted future cash flows using current market interest rates. The estimated fair value of the Company's Level 2 long-term debt was as follows:

	June 30, 2024		June 30, 2023		December 31, 2023
	(In thousands)
Carrying amount	$	2,400,617	$	2,247,422	$	2,298,223
Fair value	$	2,087,677	$	1,949,905	$	2,046,039

The carrying amounts of the Company's remaining financial instruments included in current assets and current liabilities approximate their fair values.