Income Taxes - NOLs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating loss carryforwards
Deferred tax liabilities relating to property and equipment, net operating loss and tax credit carryforwards and other temporary differences	$ 30,500
Increase in valuation allowance for state net operating loss carryforwards	200
Deferred tax liability, land	12,353	$ 12,189
Deferred Tax Liabilities, Net	42,879	42,856
Valuation allowance	3,299	3,138
Reconciliation of differences between income before income tax expense and income subject to income tax expense
Income before income tax (expense) benefit	36,272	108,026	$ 33,554
Non-taxable loss (income)	37,001	97,561	40,904
Loss (income) subject to income tax expense	(729)	10,465	(7,350)
Income tax paid
Net cash (received) paid during the period for income taxes	(5,208)	$ 653	$ 7,356
Proceeds from Income Tax Refunds	200
Income tax payments during the period	2,600
Warren Equities Inc
Income tax paid
Proceeds from Income Tax Refunds	7,600
Federal
Operating loss carryforwards
Operating loss carryforwards subject to expiration	8,900
Operating loss carryforwards not subject to expiration	66,800
State
Operating loss carryforwards
Operating loss carryforwards subject to expiration	18,900
Operating loss carryforwards not subject to expiration	$ 200