Note 3 - Acquisitions (Details) - Preliminary Allocation of Purchase Price, 2015 - USD ($) $ in Thousands		6 Months Ended
		Jun. 30, 2015	Dec. 31, 2014
Note 3 - Acquisitions (Details) - Preliminary Allocation of Purchase Price, 2015 [Line Items]
Goodwill	[1]	$ 496,482	$ 495,679
2015 Acquisitions [Member]
Note 3 - Acquisitions (Details) - Preliminary Allocation of Purchase Price, 2015 [Line Items]
Equipment and leasehold improvements		74
Goodwill		4,654
Assets acquired and liabilities assumed, net		972
Total		11,145
Customer Relationships [Member] | 2015 Acquisitions [Member]
Note 3 - Acquisitions (Details) - Preliminary Allocation of Purchase Price, 2015 [Line Items]
Finite-lived intangible assets		4,265
Trade Names [Member] | 2015 Acquisitions [Member]
Note 3 - Acquisitions (Details) - Preliminary Allocation of Purchase Price, 2015 [Line Items]
Finite-lived intangible assets		998
Noncompete Agreements [Member] | 2015 Acquisitions [Member]
Note 3 - Acquisitions (Details) - Preliminary Allocation of Purchase Price, 2015 [Line Items]
Finite-lived intangible assets		$ 182

[1] Goodwill recorded in connection with certain tax benefits to be realized in the Company's U.S. income tax returns has been reflected in the United States segment.