CONSOLIDATED STATEMENTS OF COMMON SHAREHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Treasury Stock, Common
Balance at Dec. 31, 2021	$ 2,339,713	$ 576	$ 1,716,227	$ 728,468	$ (7,310)	$ (98,248)
Shares, Balance at Dec. 31, 2021		57,606				3,546
Increase (Decrease) in Shareholders' Equity [Roll Forward]
Net Income	183,008	$ 0	0	183,008	0	$ 0
Foreign currency translation adjustment	(8)	0	0	0	(8)	0
Reclassification of net income (loss) on derivative instruments	(452)	0	0	0	(452)	0
Postretirement medical liability adjustment, net of tax	(982)	0	0	0	(982)	0
Stock based compensation, value	$ 6,480	$ 0	7,391	0	0	$ (911)
Stock based compensation, shares		87				16
Treasury Stock, Shares, Acquired	(28)
Issuance of shares, value	$ 276,582	$ 57	275,758	0	0
Issuance of shares, shares		5,585
Issuance of shares, value, treasury stock reissued						$ 767
Dividends on common stock	(140,062)	$ 0	0	(140,062)	0	0
Balance at Dec. 31, 2022	$ 2,665,183	$ 633	1,999,376	771,414	(7,848)	$ (98,392)
Shares, Balance at Dec. 31, 2022		63,278				3,534
Increase (Decrease) in Shareholders' Equity [Roll Forward]
Dividends per share	$ 2.52
Net Income	$ 194,131	$ 0	0	194,131	0	$ 0
Foreign currency translation adjustment	2	0	0	0	2	0
Reclassification of net income (loss) on derivative instruments	(452)	0	0	0	(452)	0
Postretirement medical liability adjustment, net of tax	(262)	0	0	0	(262)	0
Stock based compensation, value	$ 4,954	$ 0	4,954	0	0	$ 0
Stock based compensation, shares		51				0
Treasury Stock, Shares, Acquired	(21)
Issuance of shares, value	$ 74,904	$ 15	74,423	0	0
Issuance of shares, shares		1,433
Issuance of shares, value, treasury stock reissued						$ 466
Dividends on common stock	(154,050)	$ 0	0	(154,050)	0	0
Balance at Dec. 31, 2023	$ 2,785,314	$ 648	2,078,753	811,495	(7,656)	$ (97,926)
Shares, Balance at Dec. 31, 2023		64,762				3,513
Increase (Decrease) in Shareholders' Equity [Roll Forward]
Dividends per share	$ 2.56
Net Income	$ 224,111	$ 0	0	224,111	0	$ 0
Foreign currency translation adjustment	(4)	0	0	0	(4)	0
Reclassification of net income (loss) on derivative instruments	(452)	0	0	0	(452)	0
Postretirement medical liability adjustment, net of tax	504	0	0	0	(504)	0
Stock based compensation, value	$ 4,400	$ 0	4,672	0	0	$ (272)
Stock based compensation, shares		49				0
Treasury Stock, Shares, Acquired	(23)
Issuance of shares, value	$ 1,512	$ 0	708	0	0
Issuance of shares, shares		0
Issuance of shares, value, treasury stock reissued						$ 804
Dividends on common stock	(158,589)	$ 0	0	(158,589)	0	0
Balance at Dec. 31, 2024	$ 2,857,700	$ 648	$ 2,084,133	$ 877,017	$ (6,704)	$ (97,394)
Shares, Balance at Dec. 31, 2024		64,811				3,490
Increase (Decrease) in Shareholders' Equity [Roll Forward]
Dividends per share	$ 2.60