Note 10 - Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred Tax Assets
Loan loss allowance, due to differences in computation of bad debts	$ 52,899	$ 38,936
Share-based compensation	1,936	2,945
Accrual for bonuses	3,356	1,293
Non-accrual interest	861	1,005
Write-down on equity securities and venture capital investments	1,833	2,010
State tax	3,882	4,540
Unrealized loss on interest rate swaps	2,934	1,599
Tax credits carried forward	9,136	9,473
Net operating loss carried forward	10,880	14,247
Other, net	3,864	3,719
Gross deferred tax assets	91,581	79,767
Deferred Tax Liabilities
Deferred loan costs	(10,017)	(9,778)
Depreciation and amortization	(2,709)	(1,606)
Unrealized gain on securities available-for-sale, net	(8,712)	(5,990)
Unrealized gain on equity securities	0	(668)
OREO Installment Sale	(1,274)	0
Dividends on Federal Home Loan Bank common stock	(979)	(978)
Other, net	(3,599)	(3,307)
Gross deferred tax liabilities	(27,290)	(22,327)
Net deferred tax assets	$ 64,291	$ 57,440