Fair value measurements (Tables)

12 Months Ended

Dec. 31, 2021

Fair Value Disclosures [Abstract]

Debt Securities, Available-for-sale

Details of available-for-sale securities were as follows:

December 31, 2021	Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
	(In thousands)
Mortgage-backed securities	$	8,702	$	51	$	47	$	8,706
U.S. Treasury securities	2,407		—		11		2,396
Total	$	11,109	$	51	$	58	$	11,102

December 31, 2020	Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
	(In thousands)
Mortgage-backed securities	$	9,799	$	156	$	9	$	9,946
U.S. Treasury securities	1,386		—		5		1,381
Total	$	11,185	$	156	$	14	$	11,327

Assets and liabilities measured at fair value on a recurring basis

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

	Fair Value Measurements at December 31, 2021, 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, 2021
	(In thousands)
Assets:
Money market funds	$	—	$	10,190	$	—	$	10,190
Insurance contract*	—		109,603		—		109,603
Available-for-sale securities:
Mortgage-backed securities	—		8,706		—		8,706
U.S. Treasury securities	—		2,396		—		2,396
Total assets measured at fair value	$	—	$	130,895	$	—	$	130,895

*The insurance contract invests approximately 61 percent in fixed-income investments, 17 percent in common stock of large-cap companies, 8 percent in common stock of mid-cap companies, 7 percent in common stock of small-cap companies, 5 percent in target date investments and 2 percent in cash equivalents.

	Fair Value Measurements at December 31, 2020, 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, 2020
	(In thousands)
Assets:
Money market funds	$	—	$	8,917	$	—	$	8,917
Insurance contract*	—		100,104		—		100,104
Available-for-sale securities:
Mortgage-backed securities	—		9,946		—		9,946
U.S. Treasury securities	—		1,381		—		1,381
Total assets measured at fair value	$	—	$	120,348	$	—	$	120,348

*The insurance contract invests approximately 57 percent in fixed-income investments, 18 percent in common stock of large-cap companies, 9 percent in common stock of mid-cap companies, 9 percent in common stock of small-cap companies, 5 percent in target date investments and 2 percent in cash equivalents.

Fair value of long-term debt outstanding

The estimated fair value of the Company's Level 2 long-term debt at December 31 was as follows:

	2021		2020
	(In thousands)
Carrying Amount	$	2,741,900	$	2,213,130
Fair Value	$	2,984,866	$	2,537,289