Note 3 - Earnings Per Share (Details) - Earnings Per Common Share: (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013
Earnings Per Common Share: [Abstract]
Net income, as reported (in Dollars)	$ 11,201		$ 9,421		$ 33,182		$ 25,804
Divided by:
Weighted average common shares outstanding	29,772		29,773		29,937		30,143
Weighted average common stock equivalents	24		32		31		25
Total weighted average common shares outstanding and common stock equivalents	29,796		29,805		29,968		30,168
Basic earnings per common share (in Dollars per share)	$ 0.38		$ 0.32		$ 1.11		$ 0.86
Diluted earnings per common share(1) (in Dollars per share)	$ 0.38	[1]	$ 0.32	[1]	$ 1.11	[1]	$ 0.86	[1]
Dividend payout ratio	39.50%		40.60%		40.50%		45.30%

[1] For the three months ended September 30, 2014 and 2013, options to purchase 61,000 shares at an average exercise price of $19.37 and 111,050 shares at an average exercise price of $19.56, respectively, were not included in the computation of diluted earnings per common share as they were anti-dilutive. For the nine months ended September 30, 2014, there were no options which were considered anti-dilutive. For the nine months ended September 30, 2013, options to purchase 320,200 shares at an average exercise price of $18.33 were not included in the computation of diluted earnings per common share as they were anti-dilutive.