Fair Value Measurements (Estimated Fair Values of Financial Instruments) (Details) - USD ($) $ in Thousands		Jun. 30, 2025	Dec. 31, 2024
Carrying Amount [Member] | Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Long-term debt, including current portion	[1]	$ (1,036,894)	$ (1,036,569)
Carrying Amount [Member] | Level 2 [Member] | Interest rate contracts [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative assets related to interest rate swaps		108,111	138,354
Carrying Amount [Member] | Level 3 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Company owned life insurance asset (COLI)		6,038	6,026
Fair Value [Member] | Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Long-term debt, including current portion	[1]	(1,036,633)	(1,035,608)
Fair Value [Member] | Level 2 [Member] | Interest rate contracts [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative assets related to interest rate swaps		108,111	138,354
Fair Value [Member] | Level 3 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Company owned life insurance asset (COLI)		$ 6,038	$ 6,026

[1] The carrying amount of long-term debt includes principal and unamortized discounts.