Note 3 - Business Combinations (Details Textual) (USD $)	0 Months Ended	3 Months Ended
	Nov. 05, 2014	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014	Dec. 31, 2013
Goodwill		$ 692,454,000		$ 687,778,000
Olson [Member]
Business Acquisition, Effective Date of Acquisition	Nov. 05, 2014
Goodwill, Period Increase (Decrease)		5,100,000
Payments to Acquire Businesses, Gross	298,200,000
Goodwill		230,202,000
Business Combination, Pro Forma Information, Adjustment Operating Income		(1,900,000)
ECA [Member]
Liabilities, Fair Value Disclosure, Recurring			0		2,800,000
Liabilities, Fair Value Adjustment			$ (2,800,000)