Significant Accounting Policies (Details)	6 Months Ended	12 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Significant Accounting Policies [Line Items]
Number of days to determine non-performance of loan	90 days	90 days
Long-Term Incentive Plan Units [Member] | Director [Member]
Significant Accounting Policies [Line Items]
Vesting period	1 year	1 year
Minimum | Long-Term Incentive Plan Units [Member] | Dedicated or partially dedicated personnel [Member]
Significant Accounting Policies [Line Items]
Vesting period	1 year	1 year
Maximum | Long-Term Incentive Plan Units [Member] | Dedicated or partially dedicated personnel [Member]
Significant Accounting Policies [Line Items]
Vesting period	2 years	2 years