Note 1 - General and Basis of Presentation - Effect of Revision on Balance Sheet Line Items (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016	Jan. 01, 2016	Dec. 31, 2015
Deferred income tax liabilities	$ 77,914,000		$ 77,914,000		$ 36,411,000
Liability for unrecognized tax benefits	6,188,000		6,188,000		6,444,000
Total liabilities	1,263,231,000		1,263,231,000		1,288,525,000
Retained Earnings (Accumulated Deficit), Ending Balance	266,534,000	$ 195,241,000	266,534,000	$ 195,241,000	215,352,000		$ 152,326,000
Accumulated Other Comprehensive Income (Loss), Net of Tax, Total	(6,026,000)	(11,960,000)	(6,026,000)	(11,960,000)	(8,175,000)		(8,164,000)
Total stockholders’ equity attributable to the Company stockholders	1,156,564,000	1,043,186,000	1,156,564,000	1,043,186,000	1,076,690,000		993,434,000
Total equity	1,234,026,000	1,139,099,000	1,234,026,000	1,139,099,000	1,168,272,000		1,087,307,000
Income tax provision	(6,224,000)	(12,109,000)	(49,993,000)	(29,703,000)
Income from continuing operations	27,559,000	14,285,000	79,022,000	69,968,000
Net income attributable to the Company’s stockholders	23,960,000	11,959,000	67,794,000	65,384,000
Loss in respect of derivative instruments designated for cash flow hedge	20,000	35,000	113,000	105,000
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest, Total	29,184,000	15,633,000	81,893,000	66,172,000
Comprehensive income attributable to the Company’s stockholders	$ 25,178,000	$ 13,307,000	$ 69,943,000	$ 61,588,000
Basic: (in dollars per share)	$ 0.48	$ 0.24	$ 1.36	$ 1.32
Diluted: (in dollars per share)	$ 0.47	$ 0.24	$ 1.34	$ 1.31
Total equity	$ 1,234,026,000	$ 1,139,099,000	$ 1,234,026,000	$ 1,139,099,000	1,168,272,000		1,087,307,000
Net income			77,948,000	69,774,000
Loss in respect of derivative instruments designated for cash flow hedge	20,000	35,000	113,000	105,000
Net income	27,559,000	14,285,000	79,022,000	69,968,000
Deferred income tax provision			38,123,000	20,742,000
Liability for unrecognized tax benefits			568,000	191,000
Net cash provided by operating activities			166,533,000	158,027,000
Previously Reported [Member]
Deferred income tax liabilities	54,495,000		54,495,000		35,382,000
Liability for unrecognized tax benefits	6,188,000		6,188,000		5,738,000
Total liabilities	1,239,812,000		1,239,812,000		1,286,790,000
Retained Earnings (Accumulated Deficit), Ending Balance	289,561,000	191,627,000	289,561,000	191,627,000	216,644,000		148,396,000
Accumulated Other Comprehensive Income (Loss), Net of Tax, Total	(5,634,000)	(11,503,000)	(5,634,000)	(11,503,000)	(7,732,000)		(7,667,000)
Total stockholders’ equity attributable to the Company stockholders	1,179,983,000	1,040,029,000	1,179,983,000	1,040,029,000	1,078,425,000		990,001,000
Total equity	1,257,445,000	1,135,942,000	1,257,445,000	1,135,942,000	1,170,007,000		1,083,874,000
Income tax provision	(11,003,000)	(11,988,000)	(28,258,000)	(29,387,000)
Income from continuing operations	22,780,000	14,406,000	100,757,000	70,284,000
Net income attributable to the Company’s stockholders	19,181,000	12,080,000	89,529,000	65,700,000
Loss in respect of derivative instruments designated for cash flow hedge	20,000	22,000	62,000	65,000
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest, Total	24,405,000	15,741,000	103,577,000	66,448,000
Comprehensive income attributable to the Company’s stockholders	$ 20,399,000	$ 13,415,000	$ 91,627,000	$ 61,864,000
Basic: (in dollars per share)	$ 0.38	$ 0.24	$ 1.79	$ 1.33
Diluted: (in dollars per share)	$ 0.38	$ 0.24	$ 1.77	$ 1.31
Total equity	$ 1,257,445,000	$ 1,135,942,000	$ 1,257,445,000	$ 1,135,942,000	1,170,007,000		1,083,874,000
Net income			99,683,000	70,090,000
Loss in respect of derivative instruments designated for cash flow hedge	20,000	22,000	62,000	65,000
Net income			100,757,000	70,284,000
Deferred income tax provision			16,506,000	20,742,000
Liability for unrecognized tax benefits			450,000	(125,000)
Net cash provided by operating activities			166,533,000	158,027,000
Restatement Adjustment [Member]
Deferred income tax liabilities	23,419,000		23,419,000		1,029,000
Liability for unrecognized tax benefits					706,000
Total liabilities	23,419,000		23,419,000		1,735,000
Retained Earnings (Accumulated Deficit), Ending Balance	(23,027,000)	3,614,000	(23,027,000)	3,614,000	(1,292,000)	$ 3,900,000	3,930,000
Accumulated Other Comprehensive Income (Loss), Net of Tax, Total	(392,000)	(457,000)	(392,000)	(457,000)	(443,000)		(497,000)
Total stockholders’ equity attributable to the Company stockholders	(23,419,000)	3,157,000	(23,419,000)	3,157,000	(1,735,000)		3,433,000
Total equity	(23,419,000)	3,157,000	(23,419,000)	3,157,000	(1,735,000)		3,433,000
Income tax provision	4,779,000	(121,000)	(21,735,000)	(316,000)
Income from continuing operations	4,779,000	(121,000)	(21,735,000)	(316,000)
Net income attributable to the Company’s stockholders	4,779,000	(121,000)	(21,735,000)	(316,000)
Loss in respect of derivative instruments designated for cash flow hedge		13,000	51,000	40,000
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest, Total	4,779,000	(108,000)	(21,684,000)	(276,000)
Comprehensive income attributable to the Company’s stockholders	$ 4,779,000	$ (108,000)	$ (21,684,000)	$ (276,000)
Basic: (in dollars per share)	$ 0.10		$ (0.43)	$ (0.01)
Diluted: (in dollars per share)	$ 0.09		$ (0.43)
Total equity	$ (23,419,000)	$ 3,157,000	$ (23,419,000)	$ 3,157,000	$ (1,735,000)		$ 3,433,000
Net income			(21,735,000)	(316,000)
Loss in respect of derivative instruments designated for cash flow hedge		13,000	51,000	40,000
Net income	$ 4,800,000	$ 100,000	(21,735,000)	(316,000)
Deferred income tax provision			21,617,000
Liability for unrecognized tax benefits			118,000	316,000
Net cash provided by operating activities