Allowance for Doubtful Accounts - Impaired Notes Receivable (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Impaired Notes Receivable
Balance Beginning of Year	$ 25,704	$ 6,854
Additions	3,763	23,382
Deductions	4,830	4,532
Balance End of Year	24,637	25,704
Average Outstanding Balance	27,554	15,448
Reserve for Impaired Notes Receivable
Balance Beginning of Year	13,472	2,884
Additions	3,575	12,526
Deductions	4,557	1,938
Balance End of Year	$ 12,490	$ 13,472