Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash flows from operating activities:
Net income	$ 40,094,000	$ 11,722,000	$ 15,678,000
Adjustments to reconcile net income to net cash provided by continuing operating   activities:
Income from discontinued operations, net	0	0	(6,856,000)
Depreciation, depletion and amortization	12,946,000	6,050,000	6,158,000
Deferred income taxes	7,941,000	5,995,000	22,130,000
Gain on remeasurement of invest in real estate partnership	(51,139,000)	0	0
Equity in loss of joint ventures	5,754,000	5,690,000	1,954,000
Gain on sale of equipment and property	(880,000)	(9,184,000)	(674,000)
Stock-based compensation	1,111,000	1,372,000	232,000
Realized (gain) loss on available for sale investments	0	(298,000)	(949,000)
Deferred debt issuance cost write-off	0	902,000	0
Net changes in operating assets and liabilities:
Accounts receivable	837,000	(377,000)	18,000
Deferred costs and other assets	(346,000)	27,000	(1,072,000)
Accounts payable and accrued liabilities	1,888,000	956,000	(350,000)
Income taxes payable and receivable	3,518,000	(5,125,000)	10,358,000
Other long-term liabilities	518,000	883,000	2,138,000
Net cash provided by operating activities of continuing operations	22,242,000	18,613,000	48,765,000
Net cash used in operating activities of discontinued operations	0	0	(1,742,000)
Net cash provided by operating activities	22,242,000	18,613,000	47,023,000
Cash flows from investing activities:
Investments in properties	(16,530,000)	(17,544,000)	(10,434,000)
Investments in joint ventures	(13,436,000)	(12,315,000)	(73,529,000)
Return of capital from investments in joint ventures	22,279,000	0	0
Purchases of investments available for sale	0	(24,584,000)	(86,261,000)
Proceeds from sales of investments available for sale	69,865,000	85,735,000	116,434,000
Cash at consolidation of real estate partnership	3,704,000	0	0
Cash held in escrow	(220,000)	(10,000)	16,000
Proceeds from sale of assets	939,000	19,245,000	8,422,000
Net cash provided by (used in) investment activities of continuing operations	66,601,000	50,527,000	(45,352,000)
Net cash provided by investing activities of discontinued operations	0	0	11,533,000
Net cash provided by (used in) investing activities	66,601,000	50,527,000	(33,819,000)
Cash flows from financing activities:
Proceeds from long-term debt	92,070,000	0	0
Repayment of long-term debt	(90,000,000)	0	0
Debt issue costs	(704,000)	0	0
Distribution to noncontrolling interest	(2,602,000)	(765,000)	(1,392,000)
Repurchase of company stock	(264,000)	(21,312,000)	(8,210,000)
Exercise of employee stock options	269,000	239,000	458,000
Net cash used in financing activities of continuing operations	(1,231,000)	(21,838,000)	(9,144,000)
Net cash used in financing activities of discontinued operations	0	0	0
Net cash used in financing activities	(1,231,000)	(21,838,000)	(9,144,000)
Net increase in cash and cash equivalents	87,612,000	47,302,000	4,060,000
Cash and cash equivalents at beginning of year	73,909,000	26,607,000	22,547,000
Cash and cash equivalents at end of the year	161,521,000	73,909,000	26,607,000
Supplemental disclosures of cash flow information:
Interest, net of capitalized amounts	2,150,000	960,000	914,000
Income taxes (refunded) paid	$ (1,226,000)	$ 2,244,000	$ (26,380,000)