Note 3 - Acquisitions (Details) - Preliminary Allocation of Purchase Price, 2015 - USD ($) $ in Thousands		9 Months Ended
		Sep. 30, 2015	Dec. 31, 2014
Note 3 - Acquisitions (Details) - Preliminary Allocation of Purchase Price, 2015 [Line Items]
Goodwill	[1]	$ 489,532	$ 495,679
2015 Acquisitions [Member]
Note 3 - Acquisitions (Details) - Preliminary Allocation of Purchase Price, 2015 [Line Items]
Equipment and leasehold improvements		79
Goodwill		5,208
Assets acquired and liabilities assumed, net		904
Total		11,903
Customer Relationships [Member] | 2015 Acquisitions [Member]
Note 3 - Acquisitions (Details) - Preliminary Allocation of Purchase Price, 2015 [Line Items]
Finite-lived intangible assets		4,465
Trade Names [Member] | 2015 Acquisitions [Member]
Note 3 - Acquisitions (Details) - Preliminary Allocation of Purchase Price, 2015 [Line Items]
Finite-lived intangible assets		1,065
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.