Note 2 - Acquisition (Details) - Fair Value of Assets and Liabilities Acquired - USD ($) $ in Thousands		12 Months Ended
	Jul. 31, 2015	Dec. 31, 2015	Dec. 31, 2014
Assets acquired:
Goodwill		$ 372,189	$ 316,340
Asia Bancshares [Member]
Assets acquired:
Cash and cash equivalents	$ 63,579	63,579
Securities available-for-sale	2,370	2,370
Loans	419,219	419,219
Premises and equipment	13,291	13,291
Other real estate owned	3,048	3,048
Goodwill	55,849	55,849
Core deposit intangible	1,302	1,302
Accrued interest receivable and other assets	2,884	2,884
Total assets acquired	561,542	561,542
Liabilities assumed:
Deposits	420,623	420,623
Accrued interest payable and other liabilities	1,056	1,056
Total liabilities assumed	421,679	421,679
Net assets acquired	139,863	139,863
Cash paid	57,006	57,006
Fair value of common stock issued	82,857	82,857
Total consideration paid	$ 139,863	$ 139,863