Note 4 - Acquisition - Fair Value of Assets and Liabilities Acquired (Details) - USD ($)			3 Months Ended		6 Months Ended
	Nov. 14, 2017	Jul. 14, 2017	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Liabilities assumed:
Gain from acquisition					$ 340,000
SinoPac Bancorp [Member]
Assets acquired:
Cash and cash equivalents		$ 166,932,000
Short-term investments		122,000,000
Securities available-for-sale		88,044,000
FHLB and FRB stock		19,890,000
Loans		705,792,000
Premises and equipment		6,239,000
Cash surrender value of life insurance		46,083,000
Deferred tax assets, net		40,690,000
Core deposit intangible		6,122,000
Accrued interest receivable and other assets		10,689,000
Total assets acquired		1,212,481,000
Liabilities assumed:
Deposits		813,888,000
Advances from the Federal Home Loan Bank		30,000,000
Accrued interest payable and other liabilities		8,512,000
Total liabilities assumed		852,400,000
Net assets acquired		360,081,000
Cash paid	$ 100,000,000	284,984,000
Fair value of common stock issued		34,862,000
Total consideration paid		319,846,000
Purchase price payable to SinoPac		34,267,000
Total consideration		354,113,000
Gain from acquisition		$ 5,968,000