(9) Fair Value Measurements (Details - Level 3 Fair Value Measurements) - USD ($) $ in Thousands	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Finance receivables measured at fair value	$ 1,537,649	$ 1,559,697	$ 1,444,038	$ 1,158,365	$ 997,552	$ 821,066
Portion at Fair Value Measurement [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Finance receivables measured at fair value	1,537,649		1,444,038
Portion at Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Finance receivables measured at fair value	$ 1,537,649		$ 1,444,038
Portion at Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member] | Measurement Input, Discount Rate [Member] | Minimum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Unobservable Inputs	10.00%		8.90%
Portion at Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member] | Measurement Input, Discount Rate [Member] | Maximum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Unobservable Inputs	11.10%		11.10%
Portion at Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member] | CPS 2014-C [Member] | Minimum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Unobservable Inputs	15.30%		15.00%
Portion at Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member] | CPS 2014-C [Member] | Maximum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Unobservable Inputs	18.40%		16.10%