Notes and Other Receivables (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable	$ 74,416	$ 71,895
Secured Note Receivable, 10.00% Interest Rate, Due May 2021 [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable	$ 16,007	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	$ 34,438	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	$ 6,624	6,618
Stated interest rate	9.50%
Notes and Other Receivables from Affiliates [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable	$ 4,003	4,457
Other Receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable	$ 13,344	$ 12,944