Fair Value Measurements (Quantitative Information Level 3 Measurements ) (Details) - Level 3 - USD ($) $ in Thousands	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020
Convertible preferred securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset fair value	$ 16,803	$ 15,905	$ 11,618	$ 13,550	$ 11,649	$ 8,849
Third party appraisal | Frac sand assets | Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset fair value			2,946
Implied based on market prices | Convertible preferred securities | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset fair value	16,803		11,618	$ 13,550
Implied based on market prices | Real property | Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset fair value			$ 700
Discounted cash flow analysis | Equity method investments | Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset fair value	$ 11,538