Fair Value of Financial Instruments (Amortized Cost Basis by Year of Origination and Credit Quality Indicator) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Financing Receivable, Credit Quality Indicator [Line Items]
2020	$ 5,551
2019	16,900
2018	25,358
Total	47,809	$ 42,520
Current-period write-offs	0
Current-period recoveries	0
Current-period net write-offs	0
1-2 internal grade
Financing Receivable, Credit Quality Indicator [Line Items]
2020	5,551
2019	8,404
2018	18,770
Total	32,725
3-4 internal grade
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	8,496
2018	6,588
Total	15,084
5 internal grade
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	0
2018	0
Total	0
6 internal grade
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	0
2018	0
Total	0
7 internal grade
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	0
2018	0
Total	$ 0