Note 1 - General and Basis of Presentation - Effect of Revision on Balance Sheet Line Items (Details) - USD ($)	3 Months Ended				6 Months Ended
	Jun. 30, 2017	Mar. 31, 2017	Jun. 30, 2016	Mar. 31, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016	Jan. 01, 2016	Dec. 31, 2015
Deferred income tax liabilities	$ 72,311,000				$ 72,311,000		$ 36,411,000
Liability for unrecognized tax benefits	6,015,000				6,015,000		6,444,000
Total liabilities	1,305,334,000				1,305,334,000		1,288,525,000
Retained Earnings (Accumulated Deficit), Ending Balance	246,760,000		$ 186,753,000		246,760,000	$ 186,753,000	215,352,000		$ 152,326,000
Accumulated Other Comprehensive Income (Loss), Net of Tax, Total	(7,325,000)		(13,308,000)		(7,325,000)	(13,308,000)	(8,175,000)		(8,164,000)
Total stockholders’ equity attributable to the Company’s stockholders	1,115,076,000		1,030,321,000		1,115,076,000	1,030,321,000	1,076,690,000		993,434,000
Total equity	1,199,401,000		1,120,700,000		1,199,401,000	1,120,700,000	1,168,272,000		1,087,307,000
Income tax provision	(32,765,000)		(8,515,000)		(43,769,000)	(17,594,000)
Income from continuing operations	11,846,000		24,308,000		51,463,000	55,683,000
Net Income (Loss) Attributable to Parent, Total	8,640,000		23,724,000		43,834,000	53,425,000
Loss in respect of derivative instruments designated for cash flow hedge	45,000		35,000		93,000	70,000
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest, Total	12,421,000		22,332,000		52,709,000	50,539,000
Comprehensive income attributable to the Company’s stockholders	$ 8,808,000		$ 21,748,000		$ 44,684,000	$ 48,281,000
Basic: (in dollars per share)	$ 0.17		$ 0.48		$ 0.88	$ 1.08
Diluted: (in dollars per share)	$ 0.17		$ 0.47		$ 0.87	$ 1.07
Net income					$ 50,775,000	$ 55,683,000
Loss in respect of derivative instruments designated for cash flow hedge for the six months ended June 30, 2017	$ 45,000		$ 35,000		93,000	70,000
Net income	11,846,000		24,308,000		51,463,000	55,683,000
Deferred income tax provision					34,771,000	13,254,000
Liability for unrecognized tax benefits					395,000	(216,000)
Net cash provided by operating activities					114,158,000	119,573,000
Previously Reported [Member]
Deferred income tax liabilities	44,113,000				44,113,000		35,382,000
Liability for unrecognized tax benefits	6,015,000				6,015,000		5,738,000
Total liabilities	1,277,136,000				1,277,136,000		1,286,790,000
Retained Earnings (Accumulated Deficit), Ending Balance	274,566,000		183,018,000		274,566,000	183,018,000	216,644,000		148,396,000
Accumulated Other Comprehensive Income (Loss), Net of Tax, Total	(6,933,000)		(12,838,000)		(6,933,000)	(12,838,000)	(7,732,000)		(7,667,000)
Total stockholders’ equity attributable to the Company’s stockholders	1,143,274,000		1,027,056,000		1,143,274,000	1,027,056,000	1,078,425,000		990,001,000
Total equity	1,227,599,000		1,117,435,000		1,227,599,000	1,117,435,000	1,170,007,000		1,083,874,000
Income tax provision	(6,369,000)		(7,890,000)		(17,255,000)	(17,399,000)
Income from continuing operations	38,242,000		24,933,000		77,977,000	55,878,000
Net Income (Loss) Attributable to Parent, Total	35,036,000		24,349,000		70,348,000	53,620,000
Loss in respect of derivative instruments designated for cash flow hedge	20,000		22,000		42,000	43,000
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest, Total	38,792,000		22,944,000		79,172,000	50,707,000
Comprehensive income attributable to the Company’s stockholders	$ 35,179,000		$ 22,360,000		$ 71,147,000	$ 48,449,000
Basic: (in dollars per share)	$ 0.70		$ 0.49		$ 1.41	$ 1.09
Diluted: (in dollars per share)	$ 0.69		$ 0.49		$ 1.39	$ 1.07
Net income					$ 77,289,000	$ 55,878,000
Loss in respect of derivative instruments designated for cash flow hedge for the six months ended June 30, 2017	$ 20,000		$ 22,000		42,000	43,000
Net income					77,977,000	55,878,000
Deferred income tax provision					8,375,000	13,254,000
Liability for unrecognized tax benefits					277,000	(411,000)
Net cash provided by operating activities					114,158,000	119,573,000
Restatement Adjustment [Member]
Deferred income tax liabilities	28,198,000				28,198,000		1,029,000
Liability for unrecognized tax benefits							706,000
Total liabilities	28,198,000				28,198,000		1,735,000
Retained Earnings (Accumulated Deficit), Ending Balance	(27,806,000)		3,735,000		(27,806,000)	3,735,000	(1,292,000)	$ 3,900,000	3,930,000
Accumulated Other Comprehensive Income (Loss), Net of Tax, Total	(392,000)		(470,000)		(392,000)	(470,000)	(443,000)		(497,000)
Total stockholders’ equity attributable to the Company’s stockholders	(28,198,000)		3,265,000		(28,198,000)	3,265,000	(1,735,000)		3,433,000
Total equity	(28,198,000)		3,265,000		(28,198,000)	3,265,000	$ (1,735,000)		$ 3,433,000
Income tax provision	(26,396,000)	$ (100,000)	(625,000)	$ 400,000	(26,514,000)	(195,000)
Income from continuing operations	(26,396,000)		(625,000)		(26,514,000)	(195,000)
Net Income (Loss) Attributable to Parent, Total	(26,396,000)		(625,000)		(26,514,000)	(195,000)
Loss in respect of derivative instruments designated for cash flow hedge	25,000		13,000		51,000	27,000
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest, Total	(26,371,000)	(100,000)	(612,000)	400,000	(26,463,000)	(168,000)
Comprehensive income attributable to the Company’s stockholders	$ (26,371,000)		$ (612,000)		$ (26,463,000)	$ (168,000)
Basic: (in dollars per share)	$ (0.53)		$ (0.01)		$ (0.53)	$ (0.01)
Diluted: (in dollars per share)	$ (0.52)		$ (0.02)		$ (0.52)
Net income					$ (26,514,000)	$ (195,000)
Loss in respect of derivative instruments designated for cash flow hedge for the six months ended June 30, 2017	$ 25,000		$ 13,000		51,000	27,000
Net income		$ (100,000)	$ (600,000)	$ 400,000	(26,514,000)	(195,000)
Deferred income tax provision					26,396,000
Liability for unrecognized tax benefits					118,000	195,000
Net cash provided by operating activities