Note 8 - Deposits - Remaining Maturities of Certificate of Deposit Accounts (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Total certificate of deposit accounts	$ 1,563,310	$ 1,351,933
Certificates of Deposit [Member]
Within 12 months	1,017,177	759,360
More than 12 months to 24 months	404,930	449,293
More than 24 months to 36 months	78,427	95,626
More than 36 months to 48 months	10,915	42,928
More than 48 months to 60 months	51,365	2,648
More than 60 months	496	2,078
Total certificate of deposit accounts	$ 1,563,310	$ 1,351,933