Note 16 - Supplemental Selected Quarterly Financial Data (Unaudited) (Details) - Supplemental Selected Quarterly Financial Data (USD $)	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Fiscal Year 2014
Revenues	$ 1,118,416,000us-gaap_SalesRevenueNet	$ 1,042,356,000us-gaap_SalesRevenueNet	$ 983,953,000us-gaap_SalesRevenueNet
Operating income	130,596,000us-gaap_OperatingIncomeLoss	94,445,000us-gaap_OperatingIncomeLoss	92,275,000us-gaap_OperatingIncomeLoss
Income from continuing operations - diluted	79,009,000	52,622,000	50,453,000
Net income	102,278,000us-gaap_NetIncomeLoss	65,323,000us-gaap_NetIncomeLoss	60,032,000us-gaap_NetIncomeLoss
Income per common share -basic:
Income from continuing operations - basic	$ 0.95	$ 0.62	$ 0.58
Net income - basic	$ 1.23us-gaap_EarningsPerShareBasic	$ 0.77us-gaap_EarningsPerShareBasic	$ 0.69us-gaap_EarningsPerShareBasic
Income per common share -diluted:
Income from continuing operations	$ 0.84	$ 0.56	$ 0.53
Net income - diluted	$ 1.07us-gaap_EarningsPerShareDiluted	$ 0.69us-gaap_EarningsPerShareDiluted	$ 0.62us-gaap_EarningsPerShareDiluted
First Quarter [Member]
Fiscal Year 2014
Revenues	242,824,000	267,923,000
Operating income	20,757,000	24,861,000
Income from continuing operations - diluted	11,742,000	160
Net income	35,011,000	17,375,000
Income per common share -basic:
Income from continuing operations - basic	$ 0.14	$ 0.18
Net income - basic	$ 0.41	$ 0.21
Income per common share -diluted:
Income from continuing operations	$ 0.13	$ 14,867
Net income - diluted	$ 0.36	$ 0.18
Second Quarter [Member]
Fiscal Year 2014
Revenues	272,466,000	259,376,000
Operating income	31,816,000	21,596,000
Income from continuing operations - diluted	20,329,000	130
Net income	20,329,000	15,664,000
Income per common share -basic:
Income from continuing operations - basic	$ 0.24	$ 0.14
Net income - basic	$ 0.24	$ 0.19
Income per common share -diluted:
Income from continuing operations	$ 0.21	$ 11,859
Net income - diluted	$ 0.21	$ 0.17
Third Quarter [Member]
Fiscal Year 2014
Revenues	296,964,000	268,132,000
Operating income	39,432,000	25,645,000
Income from continuing operations - diluted	23,492,000	160
Net income	23,492,000	18,760,000
Income per common share -basic:
Income from continuing operations - basic	$ 0.29	$ 0.18
Net income - basic	$ 0.29	$ 0.22
Income per common share -diluted:
Income from continuing operations	$ 0.25	$ 15,431
Net income - diluted	$ 0.25	$ 0.20
Fourth Quarter [Member]
Fiscal Year 2014
Revenues	306,162,000	246,925,000
Operating income	38,591,000	22,343,000
Income from continuing operations - diluted	23,446,000	110
Net income	$ 23,446,000	$ 13,524,000
Income per common share -basic:
Income from continuing operations - basic	$ 0.29	$ 0.12
Net income - basic	$ 0.29	$ 0.16
Income per common share -diluted:
Income from continuing operations	$ 0.25	$ 10,465
Net income - diluted	$ 0.25	$ 0.14

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