Note 2 - Basic and Diluted Earnings Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended			6 Months Ended		9 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Mar. 31, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Net income	$ 8,531	$ 8,357	$ 18,545	$ 16,724	$ 18,545	$ 17,200
Basic earnings per common share - weighted-average shares (in shares)	32,441	33,582		32,448	33,521
Effect of dilutive stock options (in shares)	192	271		186	281
Diluted earnings per common share - weighted-average shares and assumed conversions (in shares)	32,633	33,853		32,634	33,802
Basic earnings per common share (in dollars per share)	$ 0.26	$ 0.25		$ 0.52	$ 0.55
Diluted earnings per common share (in dollars per share)	$ 0.26	$ 0.25		$ 0.51	$ 0.55