Accumulated Other Comprehensive Income (Loss) (Components of AOCI) (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended		12 Months Ended
	Jun. 30, 2025	Mar. 31, 2025	Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2025	Jun. 30, 2024	Dec. 31, 2024	Dec. 31, 2023
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	$ (700,813)	$ (748,742)	$ (673,441)	$ (646,568)	$ (748,742)	$ (646,568)	$ (646,568)
Other comprehensive income (loss) before reclassifications (3)	108,511		(27,981)		154,548	(55,710)
Amounts reclassified from AOCL	1,873		4,393		3,765	5,249
Other comprehensive income (loss):	110,384		(23,588)		158,313	(50,461)
Ending balance	(590,429)	(700,813)	(697,029)	(673,441)	(590,429)	(697,029)	(748,742)	$ (646,568)
Foreign currency translation adjustment		(7,300)		(7,200)	(7,200)	(7,300)	(7,300)	(7,000)
Foreign currency translation items
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(584,526)	(632,097)	(552,117)	(523,873)	(632,097)	(523,873)	(523,873)
Other comprehensive income (loss) before reclassifications (3)	111,659		(27,997)		159,230	(56,241)
Amounts reclassified from AOCL	0		3,566		0	3,566
Other comprehensive income (loss):	111,659		(24,431)		159,230	(52,675)
Ending balance	(472,867)	(584,526)	(576,548)	(552,117)	(472,867)	(576,548)	(632,097)	(523,873)
Pension and other postretirement effects
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(115,564)	(115,898)	(120,506)	(121,882)	(115,898)	(121,882)	(121,882)
Other comprehensive income (loss) before reclassifications (3)	(3,148)		16		(4,682)	531
Amounts reclassified from AOCL	1,849		803		3,717	1,664
Other comprehensive income (loss):	(1,299)		819		(965)	2,195
Ending balance	(116,863)	(115,564)	(119,687)	(120,506)	(116,863)	(119,687)	(115,898)	(121,882)
Cash flow hedging activity
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(723)	(747)	(818)	(813)	(747)	(813)	(813)
Other comprehensive income (loss) before reclassifications (3)	0		0		0	0
Amounts reclassified from AOCL	24		24		48	19
Other comprehensive income (loss):	24		24		48	19
Ending balance	(699)	$ (723)	(794)	$ (818)	(699)	(794)	$ (747)	$ (813)
Non- controlling Interests
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Other comprehensive income (loss):	$ 60		$ (72)		$ 93	$ (285)