Note 8 - Income Taxes (Details) - Reconciliation of Income Tax Expense - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Reconciliation of Income Tax Expense [Abstract]
Computed at the statutory rate (35%)			$ 15,142	$ 6,880
Increase (decrease) in taxes resulting from:
State income taxes, net of federal tax benefit			1,432	460
Tax exempt interest income			(2,284)	(1,868)
Tax exempt earnings on BOLI			(364)	(247)
Merger related expenses			569
Federal tax credits			(276)
Other differences, net			213	171
Actual tax provision	$ 10,250	$ 4,464	$ 14,432	$ 5,396