Fair Value Disclosure (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023	Dec. 31, 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gain (loss) on equity securities	$ 442	$ (551)	$ 1,219	$ 498
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	17,987		17,987		$ 17,208
Gain (loss) on equity securities	(100)	(200)	(300)	(200)
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value Measurements, Recurring | Bellaire
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gain (loss) on equity securities	600	$ (400)	1,500	$ 700
Quoted Prices in Active Markets for Identical Assets (Level 1) | Reported Value Measurement | Fair Value Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities cost						$ 2,000
Quoted Prices in Active Markets for Identical Assets (Level 1) | Reported Value Measurement | Fair Value Measurements, Recurring | Other Noncurrent Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	5,700		5,700		6,000
Quoted Prices in Active Markets for Identical Assets (Level 1) | Reported Value Measurement | Fair Value Measurements, Recurring | Bellaire
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities cost						$ 5,000
Quoted Prices in Active Markets for Identical Assets (Level 1) | Reported Value Measurement | Fair Value Measurements, Recurring | Bellaire | Other Noncurrent Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	$ 12,300		$ 12,300		$ 11,200