Note 4 - Income Per Share - Percentage of Net Earnings Allocable to Common Shareholders (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Weighted average participating common shares (in shares)	35,528,094	32,419,016	35,091,624	32,224,577
Weighted average participating common shares (in shares)	35,528,094	32,419,016	35,091,624	32,224,577
Add: Weighted average shares of Convertible Preferred Stock (in shares)		212,967		233,984
Weighted average participating shares (in shares)	35,528,094	32,631,983	35,091,624	32,458,561
Portion allocable to common shareholders	100.00%	99.30%	100.00%	99.30%