Note 6 - Earnings per Share (Detail) - Summary of Earnings and Weighted Average Number of Common Shares Used in the Calculation of Basic and Diluted Earnings Per Share (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Basic:
Weighted average common shares outstanding, basic	13,845,516	13,796,715	13,842,797	13,738,748
Net income (in Dollars)	$ 13,614	$ 13,611	$ 26,290	$ 32,335
Dividends to preferred stockholders (in Dollars)	(2,168)	(2,168)	(4,336)	(4,336)
Net income available to common stockholders (in Dollars)	11,446	11,443	21,954	27,999
Add dilutive preferred stock dividends for effect of assumed conversion of preferred stock (in Dollars)				4,336
Earnings per common share, basic (in Dollars per share)	$ 0.83	$ 0.83	$ 1.59	$ 2.04
Diluted:
Dilutive effect of contingent issuable stock	117,000		83,572
Convertible preferred stock				2,623,552
Assumed average common shares outstanding	13,975,073	13,816,191	13,941,674	16,383,703
Net income for diluted earnings per common share (in Dollars)	$ 11,446	$ 11,443	$ 21,954	$ 32,335
Earnings per common share, diluted (in Dollars per share)	$ 0.82	$ 0.83	$ 1.57	$ 1.97
Restricted Stock [Member]
Diluted:
	3,431	5,108	5,805	6,939
Stock Options [Member]
Diluted:
	9,126	14,368	9,500	14,464