Amount after allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards.

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Note 3 - Recent Accounting Pronouncements - Cumulative Effect of Changes (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Jan. 01, 2021	Dec. 31, 2020	Mar. 31, 2020	Dec. 31, 2019
Allowance for credit losses on loans	$ 147,264		$ 166,538
Deferred tax assets			85,610
Allowance for unfunded commitments			5,880
Stockholders' equity	$ 2,463,289		$ 2,418,144	$ 2,313,037	$ 2,294,283
Cumulative Effect, Period of Adoption, Adjustment [Member]
Allowance for credit losses on loans		$ 594
Deferred tax assets		335
Allowance for unfunded commitments		539
Stockholders' equity		(798)
Cumulative Effect, Period of Adoption, Adjusted Balance [Member]
Allowance for credit losses on loans		167,132
Deferred tax assets		85,945
Allowance for unfunded commitments		6,419
Stockholders' equity		$ 2,417,346