Note 18 - Concentration of Third-party Mortgage Purchasers - Percent of Mortgage Loans Sold to Third-party Purchasers (Details) - Customer Concentration Risk [Member] - Mortgage Loans Sold [Member]	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
PennyMac Loan Services, LLC [Member]
Percentage of mortgage loans sold to third-party purchasers	23.00%	17.00%	15.00%
Fannie Mae [Member]
Percentage of mortgage loans sold to third-party purchasers	11.00%	11.00%	10.00%
U.S. Bancorp [Member]
Percentage of mortgage loans sold to third-party purchasers	11.00%	9.00%	7.00%
SunTrust Mortgage, Inc. [Member]
Percentage of mortgage loans sold to third-party purchasers	11.00%	8.00%	8.00%
Flagstar Bancorp, Inc. [Member]
Percentage of mortgage loans sold to third-party purchasers	11.00%	6.00%	0.00%
Wells Fargo Funding, Inc. [Member]
Percentage of mortgage loans sold to third-party purchasers	9.00%	13.00%	26.00%
Ginnie Mae [Member]
Percentage of mortgage loans sold to third-party purchasers	5.00%	11.00%	9.00%