Supplemental Stockholders' Equity Information - Changes in Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance, beginning of period	$ 1,763,219	$ 1,599,972
Other comprehensive loss before reclassifications, before tax	(2,555)
Amounts reclassified from accumulated other comprehensive loss, before tax	3,288
Income tax (benefit)/expense	230
Net current-period other comprehensive (loss)/income, net of tax	503	3,709
Balance, end of period	1,747,962	1,576,790
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance, beginning of period	910
Other comprehensive loss before reclassifications, before tax	(1,846)
Amounts reclassified from accumulated other comprehensive loss, before tax	0
Income tax (benefit)/expense	(483)
Net current-period other comprehensive (loss)/income, net of tax	(1,363)
Balance, end of period	(453)
Funded Status of Benefit Plans
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance, beginning of period	(353,286)
Other comprehensive loss before reclassifications, before tax	0
Amounts reclassified from accumulated other comprehensive loss, before tax	3,288
Income tax (benefit)/expense	899
Net current-period other comprehensive (loss)/income, net of tax	2,389
Balance, end of period	(350,897)
Net Unrealized Loss on Available-For-Sale Securities
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance, beginning of period	(486)
Other comprehensive loss before reclassifications, before tax	(709)
Amounts reclassified from accumulated other comprehensive loss, before tax	0
Income tax (benefit)/expense	(186)
Net current-period other comprehensive (loss)/income, net of tax	(523)
Balance, end of period	(1,009)
Total Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance, beginning of period	(352,862)	(357,847)
Net current-period other comprehensive (loss)/income, net of tax	503	3,709
Balance, end of period	$ (352,359)	$ (354,138)