Note 14 - Condensed Consolidating Financial Information of Guarantor Subsidiaries (Details) - Condensed Consolidating Statement of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by operating activities	$ 50,030	$ 45,199	$ 36,355
Investing activities:
Cash paid for acquisitions, net	(75,235)	(187,402)	(3,318)
Purchases of equipment and leasehold improvements, net	(11,190)	(10,894)	(6,544)
Working capital and other settlements for acquisitions	(212)	(2,331)	(569)
Proceeds from foreign currency net investment hedge	7,698	4,006	1,421
Other	(1,499)	(1,542)	(1,144)
Net cash used in investing activities	(80,438)	(198,163)	(10,154)
Financing activities:
Borrowings under senior unsecured notes	500,000
Borrowings under senior secured revolving credit facility	25,478	299,255	142,473
Proceeds from the exercise of options and warrants	14,423	42,437	24,261
Excess tax benefit related to share-based compensation	2,591	9,287	6,610
Net borrowings (repayments) under working capital facilities	(3,362)	4,939	2,772
Payment of deferred financing costs	(9,035)	(263)	(172)
Payment for early redemption of senior unsecured notes	(14,618)
Purchases of stock for treasury	(21,268)
Repayment of subordinated unsecured notes payable		(333)	(270)
Payment of contingent earnout obligation	(5,064)	(4,362)
Repayment under senior secured revolving credit facility	(169,330)	(200,429)	(196,746)
Repayments under senior unsecured notes	(250,000)
Intercompany notes and investments and other		(53)
Net cash provided by (used in) financing activities	69,815	150,478	(21,072)
Exchange rate impact on cash and cash equivalents	(1,293)	(592)	(927)
Net increase (decrease) in cash and cash equivalents	38,114	(3,078)	4,202
Cash and cash equivalents, beginning of year	9,751	12,829	8,627
Cash and cash equivalents, end of year	47,865	9,751	12,829
Guarantor Subsidiaries [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by operating activities	30,000	33,096	23,963
Investing activities:
Cash paid for acquisitions, net	(22,697)	(177,864)	(592)
Purchases of equipment and leasehold improvements, net	(7,171)	(7,687)	(3,197)
Working capital and other settlements for acquisitions	(181)	(477)	(444)
Proceeds from foreign currency net investment hedge	7,698	4,006	1,421
Other	(1,499)	(1,347)	(1,144)
Net cash used in investing activities	(23,850)	(183,369)	(3,956)
Financing activities:
Repayment of subordinated unsecured notes payable		(333)	(270)
Intercompany notes and investments and other	26,472	150,234	(23,102)
Net cash provided by (used in) financing activities	26,472	149,901	(23,372)
Net increase (decrease) in cash and cash equivalents	32,622	(372)	(3,365)
Cash and cash equivalents, beginning of year	388	760	4,125
Cash and cash equivalents, end of year	33,011	388	760
Non-Guarantor Subsidiaries [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by operating activities	20,030	12,103	12,392
Investing activities:
Cash paid for acquisitions, net	(52,538)	(9,538)	(2,726)
Purchases of equipment and leasehold improvements, net	(4,019)	(3,207)	(3,347)
Working capital and other settlements for acquisitions	(31)	(1,854)	(125)
Other		(195)
Net cash used in investing activities	(56,588)	(14,794)	(6,198)
Financing activities:
Net borrowings (repayments) under working capital facilities	(3,362)	4,939	2,772
Payment of deferred financing costs	(144)		(116)
Payment of contingent earnout obligation	(5,064)	(4,362)
Intercompany notes and investments and other	51,913		(356)
Net cash provided by (used in) financing activities	(43,343)	577	2,300
Exchange rate impact on cash and cash equivalents	(1,293)	(592)	(927)
Net increase (decrease) in cash and cash equivalents	5,492	(2,706)	7,567
Cash and cash equivalents, beginning of year	9,363	12,069	4,502
Cash and cash equivalents, end of year	14,854	9,363	12,069
Parent Company [Member]
Financing activities:
Borrowings under senior unsecured notes	500,000
Borrowings under senior secured revolving credit facility	25,478	299,255	142,473
Proceeds from the exercise of options and warrants	14,423	42,437	24,261
Excess tax benefit related to share-based compensation	2,591	9,287	6,610
Payment of deferred financing costs	(8,891)	(263)	(56)
Payment for early redemption of senior unsecured notes	(14,618)
Purchases of stock for treasury	(21,268)
Repayment under senior secured revolving credit facility	(169,330)	(200,429)	(196,746)
Repayments under senior unsecured notes	(250,000)
Intercompany notes and investments and other	$ (78,385)	$ (150,287)	$ 23,458