Schedule 1 - Condensed Parent Company Financial Statements (Condensed Statements of Income and Comprehensive Income) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Condensed Income Statements, Captions [Line Items]
Operating income	$ 692,097	$ 661,187	$ 602,709
Interest expense	283,362	238,116	207,709
Other (income) expense	(2,613)	494	(2,848)
Income before income taxes	431,781	450,908	422,000
Income tax benefit	(66,445)	(14,329)	(9,612)
Net income	498,226	465,237	431,612
Comprehensive income	$ 498,226	$ 465,237	$ 431,612
Basic	$ 1.86	$ 1.77	$ 1.68
Diluted	$ 1.86	$ 1.77	$ 1.67
Basic	267,171	262,246	257,487
Diluted	267,659	262,868	258,180
Parent Company [Member]
Condensed Income Statements, Captions [Line Items]
Other income	$ 2,985	$ 5,368	$ 8,388
Operating expense and other expenses	6,479	10,724	5,821
Operating income	(3,494)	(5,356)	2,567
Interest expense	64,031	35,817	21,729
Interest income	(348)	(107)	(9)
Other (income) expense	(584)	893	(609)
Income before income taxes	(66,593)	(41,959)	(18,544)
Equity in earnings of subsidiaries	547,617	495,556	445,951
Income before income taxes	481,024	453,597	427,407
Income tax benefit	(17,202)	(11,640)	(4,205)
Net income	498,226	465,237	431,612
Comprehensive income	$ 498,226	$ 465,237	$ 431,612
Basic	$ 1.86	$ 1.77	$ 1.68
Diluted	$ 1.86	$ 1.77	$ 1.67
Basic	267,171	262,246	257,487
Diluted	267,659	262,868	258,180