Note 2 - Net Income Per Share Net Income Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Schedule of Earnings Per Share, Basic and Diluted, by Common Class, Including Two Class Method [Table] [Line Items]
Net income from continuing operations - basic		$ 98,112	$ 45,193	$ 164,361	$ 136,920
Net income From continuing operations - diluted		99,025	48,900	168,664	144,300
Income (loss) from discontinued operations, net of tax		0	4,855	0	5,385
Net income - basic		98,112	50,048	164,361	142,305
Net income - diluted		$ 99,025	$ 53,755	$ 168,664	$ 149,685
Average common shares outstanding - basic		214,274	193,112	208,991	192,245
Dilutive effect of stock-based compensation arrangements (2)	[1]	2,989	3,364	2,698	3,211
Adjusted average common shares outstanding - diluted		226,203	246,650	232,945	244,981
Net income from continuing operations, per basic share		$ 0.46	$ 0.23	$ 0.79	$ 0.71
Income from discontinued operations and disposal of discontinued operations, net of tax, per basic share		0.00	0.03	0.00	0.03
Net income per share - basic		0.46	0.26	0.79	0.74
Net income from continuing operations, per diluted share		0.44	0.20	0.73	0.59
Income from discontinued operations and disposal of discontinued operations, net of tax, per diluted share		0.00	0.02	0.00	0.02
Net income per share - diluted		$ 0.44	$ 0.22	$ 0.73	$ 0.61
Stock Compensation Plan [Member]
Schedule of Earnings Per Share, Basic and Diluted, by Common Class, Including Two Class Method [Table] [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount		1,042	264	1,042	530
Convertible Debt Securities [Member]
Schedule of Earnings Per Share, Basic and Diluted, by Common Class, Including Two Class Method [Table] [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount		0	0	1,902	0
Convertible Debt | Convertible Senior Notes Due 2019
Schedule of Earnings Per Share, Basic and Diluted, by Common Class, Including Two Class Method [Table] [Line Items]
Adjustment for dilutive Convertible Senior Notes due 2019, net of tax (1)	[2]	$ 913	$ 3,707	$ 4,303	$ 7,380
Dilutive effect of Convertible Senior Notes		8,928	37,736	21,256	37,736
Convertible Debt | Convertible Senior Notes Due 2017
Schedule of Earnings Per Share, Basic and Diluted, by Common Class, Including Two Class Method [Table] [Line Items]
Dilutive effect of Convertible Senior Notes	[1]	12	12,438	0	11,789

[1] The following number of shares of our common stock equivalents issued under our stock-based compensation arrangements and convertible debt were not included in the calculation of net income per share because they were anti-dilutive: Three Months EndedJune 30, Six Months EndedJune 30,(in thousands)2016 2015 2016 2015Shares of common stock equivalents1,042 264 1,042 530Shares of Convertible Senior Notes due 2017— — 1,902 —

[2] As applicable, includes coupon interest, amortization of discount and fees, and other changes in income or loss that would result from the assumed conversion.