Note 3 - Earnings Per Share (Details) - Earnings Per Common Share - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Earnings Per Common Share [Abstract]
Net income, as reported (in Dollars)		$ 11,008	$ 11,201	$ 34,575	$ 33,182
Divided by:
Weighted average common shares outstanding		28,927	29,772	29,188	29,937
Weighted average common stock equivalents		19	24	21	31
Total weighted average common shares outstanding and common stock equivalents		28,946	29,796	29,209	29,968
Basic earnings per common share (in Dollars per share)		$ 0.38	$ 0.38	$ 1.18	$ 1.11
Diluted earnings per common share (1) (in Dollars per share)	[1]	$ 0.38	$ 0.38	$ 1.18	$ 1.11
Dividend payout ratio		42.10%	39.50%	40.70%	40.50%

[1] For the three and nine months ended September 30, 2015 and 2014, there were no stock options that were anti-dilutive.