Note 6 - Goodwill and Other Intangible Assets (Details) - Goodwill and Other Intangibles - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Note 6 - Goodwill and Other Intangible Assets (Details) - Goodwill and Other Intangibles [Line Items]
Goodwill	$ 314,282	$ 108,095
Core deposit premiums:
Net carrying amount	44,904
Total goodwill and other intangible assets	359,186	130,621
Core Deposit Premium [Member]
Core deposit premiums:
Gross carrying amount	43,648	18,318
Accumulated amortization	(5,135)	(2,386)
Net carrying amount	38,513	15,932
Purchased Credit Card Relationships [Member]
Core deposit premiums:
Gross carrying amount	2,068	2,068
Accumulated amortization	(827)	(517)
Net carrying amount	1,241	1,551
Books of Business Intangible [Member]
Core deposit premiums:
Gross carrying amount	5,560	5,140
Accumulated amortization	(410)	(97)
Net carrying amount	5,150	5,043
Other Intangible Assets [Member]
Core deposit premiums:
Net carrying amount	$ 44,904	$ 22,526