Fair Value Disclosure (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Realized gain (loss) on equity securities	$ 1,512	$ 261	$ 316	$ 959
Investment in equity securities			2,000	0
Level 1 | Fair value measurements, recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	12,486		12,486		$ 10,120
Realized gain (loss) on equity securities	400		400
Bellaire Corporation | Level 1 | Fair value measurements, recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Realized gain (loss) on equity securities	1,100	$ 300	$ (100)	$ 1,000
Carrying Value | Level 1 | Fair value measurements, recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment in equity securities	$ 2,000
Carrying Value | Bellaire Corporation | Level 1 | Fair value measurements, recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities						$ 5,000