Note 6 - Stockholders' Equity (Detail) - RSU Summary (USD $)	12 Months Ended		12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2012 Restricted Stock Units (RSUs) [Member]	Dec. 31, 2011 Restricted Stock Units (RSUs) [Member]	Dec. 31, 2010 Restricted Stock Units (RSUs) [Member]	Dec. 31, 2008 Restricted Stock Units (RSUs) [Member]	Dec. 31, 2012 Performance Based Restricted Stock Unit [Member]	Dec. 31, 2011 Performance Based Restricted Stock Unit [Member]	Dec. 31, 2010 Performance Based Restricted Stock Unit [Member]	Dec. 31, 2008 Performance Based Restricted Stock Unit [Member]
Stock Unit	1,299,556	960,174		289,896	1,082,431	616,549		289,896	217,125	343,625		0
Weighted Average Grant Date Fair Value Per Share (in Dollars per share)	$ 16.87	$ 19.88		$ 18.67	$ 16.00	$ 19.41		$ 18.67	$ 20.73	$ 20.73		$ 0
Weighted Average Remaining Recognition Period	2 years 65 days	2 years 259 days	2 years 332 days	2 years 80 days
Awards modification (1) (in Dollars)	$ 0				$ (76,500)				$ 76,500
Awards modification (1)	0				15.69				15.69
Stock Unit	973,836	853,480	934,240		617,084	853,480	518,240		356,752	0	416,000
Weighted Average Grant Date Fair Value Per Share (in Dollars per share)	$ 18.57	$ 14.40	$ 20.05		$ 18.69	$ 14.40	$ 19.50		$ 18.38	$ 0	$ 20.73
Performance awards adjustment (3) (in Dollars)	(18,359)				0				(18,359)
Performance awards adjustment (3) (in Dollars)	$ 19.18				$ 0				$ 19.18
Stock Unit	(543,596)	(413,101)	(230,874)		(447,096)	(310,976)	(158,499)		(96,500)	(102,125)	(72,375)
Weighted Average Grant Date Fair Value Per Share (in Dollars per share)	$ 17.91	$ 18.51	$ 19.24		$ 17.30	$ 17.78	$ 18.56		$ 20.73	$ 20.73	$ 20.73
Stock Unit	(81,689)	(100,997)	(33,088)		(77,356)	(76,622)	(33,088)		(4,333)	(24,375)	0
Weighted Average Grant Date Fair Value Per Share (in Dollars per share)	$ 16.74	$ 18.95	$ 18.38		$ 16.61	$ 18.39	$ 18.38		$ 19.07	$ 20.73	$ 0
Stock Unit	1,629,748	1,299,556	960,174		1,098,563	1,082,431	616,549	289,896	531,185	217,125	343,625	0
Weighted Average Grant Date Fair Value Per Share (in Dollars per share)	$ 17.46	$ 16.87	$ 19.88		$ 16.96	$ 16.00	$ 19.41	$ 18.67	$ 18.49	$ 20.73	$ 20.73	$ 0

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Stock-based compensation related to awards modification

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Adjustments to performance-based RSUs.

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The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

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Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The weighted average fair value of nonvested awards on equity-based plans excluding option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, revenue or profit achievement stock award plan) for which the employer is contingently obligated to issue equity instruments or transfer assets to an employee who has not yet satisfied service or performance criteria necessary to gain title to proceeds from the sale of the award or underlying shares or units.

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The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan.

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