Note 3 - Earnings Per Share (Details) - Earnings per common share: (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2013		Jun. 30, 2012		Jun. 30, 2013		Jun. 30, 2012
Earnings per common share: [Abstract]
Net income, as reported (in Dollars)	$ 9,627		$ 8,637		$ 16,383		$ 15,766
Divided by:
Weighted average common shares outstanding	30,213		30,472		30,330		30,434
Weighted average common stock equivalents	22		20		27		22
Total weighted average common shares outstanding and common stock equivalents	30,235		30,492		30,357		30,456
Basic earnings per common share (in Dollars per share)	$ 0.32		$ 0.28		$ 0.54		$ 0.52
Diluted earnings per common share (1) (in Dollars per share)	$ 0.32	[1]	$ 0.28	[1]	$ 0.54	[1]	$ 0.52	[1]
Dividend payout ratio	40.60%		46.40%		48.10%		50.00%

[1] For the three and six months ended June 30, 2013, options to purchase 542,340 shares at an average exercise price of $17.66 were not included in the computation of diluted earnings per common share as they are anti-dilutive. For the three and six months ended June 30, 2012, options to purchase 720,865 shares at an average exercise price of $16.71 were not included in the computation of diluted earnings per common share as they are anti-dilutive.