Notes and Other Receivables (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable	$ 71,154	$ 71,895
Secured Note Receivable, 10.00% Interest Rate, Due May 2021 [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable	$ 15,609	15,226
Stated interest rate	10.00%
Secured Note Receivable, 10.75% Interest Rate, Due September 2020 [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable	$ 33,527	32,650
Stated interest rate	10.75%
Secured Note Receivable, 9.50% Interest Rate, Due October 2019 [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable	$ 6,621	6,618
Stated interest rate	9.50%
Notes and Other Receivables from Affiliates [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable	$ 3,889	4,457
Other Receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable	$ 11,508	$ 12,944