Transactions with Affiliates - Other Transactions, Conditional Reimbursement (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Aug. 04, 2009
Maximum
Conditional reimbursement
Conditional reimbursement				$ 2,900,000
Conditional Reimbursement
Conditional reimbursement
Payments received	$ 69,000	$ 30,000	$ 0