Note 2 - Significant Accounting Policies and Consolidated Financial Statement Components - Summary of Troubled Debt Restructurings (Details) $ in Thousands		12 Months Ended
		Mar. 31, 2019 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2018 USD ($)
Amount of TDRs on non-accrual status (in thousands)		$ 29,200	$ 26,400
Point-of-Sale [Member]
Number of TDRs		8,604		8,722
Amount of TDRs on non-accrual status (in thousands)		$ 11,712		$ 12,178
Carrying value of TDRs (in thousands)		$ 8,015		7,535
Number of accounts		2,279	2,753
Loan balance at time of charge off (in thousands)		$ 3,607	$ 4,322
Point-of-Sale [Member] | Performing Financial Instruments [Member]
Carrying value of TDRs (in thousands)	[1]	6,426		5,788
Point-of-Sale [Member] | Nonperforming Financial Instruments [Member]
Carrying value of TDRs (in thousands)	[1]	$ 1,589		$ 1,747
Point-of-Sale [Member] | Extended Maturity [Member]
Number of TDRs		2,737		2,414
Amount of TDRs on non-accrual status (in thousands)		$ 4,779		$ 3,876
Direct-to-Consumer [Member]
Number of TDRs		6,515		3,003
Amount of TDRs on non-accrual status (in thousands)		$ 6,160		$ 3,193
Carrying value of TDRs (in thousands)		$ 4,033		1,524
Number of accounts		1,985	1,245
Loan balance at time of charge off (in thousands)		$ 2,168	$ 2,415
Direct-to-Consumer [Member] | Performing Financial Instruments [Member]
Carrying value of TDRs (in thousands)	[1]	3,449		1,208
Direct-to-Consumer [Member] | Nonperforming Financial Instruments [Member]
Carrying value of TDRs (in thousands)	[1]	$ 584		$ 316
Direct-to-Consumer [Member] | Extended Maturity [Member]
Number of TDRs		1,503		236
Amount of TDRs on non-accrual status (in thousands)		$ 1,608		$ 262

[1] "TDRs - Performing" include accounts that are current on all amounts owed, while "TDRs - Nonperforming" include all accounts with past due amounts owed.