Intangible Assets (Components of Finite-Lived Intangible Assets) (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
Jun. 30, 2011 years	Dec. 31, 2010
Gross book value	$ 163,597	$ 89,853
Accumulated amortization	(68,571)	(66,690)
Customer Relationships [Member]
Gross book value	83,212	37,028
Accumulated amortization	(37,168)	(30,283)
Estimated useful life (in years), minimum	4
Estimated useful life (in years), maximum	7
Database [Member]
Gross book value	492	13,292
Accumulated amortization	(410)	(12,421)
Estimated useful life (in years), minimum	3
Estimated useful life (in years), maximum	6
Trade Names [Member]
Gross book value	11,594	10,601
Accumulated amortization	(6,806)	(6,135)
Estimated useful life (in years), minimum	2
Estimated useful life (in years), maximum	10
Technology [Member]
Gross book value	55,540	27,543
Accumulated amortization	(22,024)	(16,991)
Estimated useful life (in years), minimum	1
Estimated useful life (in years), maximum	5
Non-compete Agreements [Member]
Gross book value	6,569	1,389
Accumulated amortization	(1,733)	(860)
Estimated useful life (in years), minimum	4
Estimated useful life (in years), maximum	5
State DMV Relationships [Member]
Gross book value	6,190
Accumulated amortization	$ (430)
Estimated useful life (in years),average	6

The accumulated amount of amortization of a major finite-lived intangible asset class. A major class is composed of intangible assets that can be grouped together because they are similar, either by their nature or by their use in the operations of a company.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 142
-Paragraph 45
-Subparagraph a(1)
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=6905858&loc=d3e16323-109275

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- Definition

The average useful life of a major finite-lived intangible asset class. A major class is composed of intangible assets that can be grouped together because they are similar either by their nature or by their use in the operations of a company.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=6905858&loc=d3e16265-109275

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- Definition

Sum of the gross carrying amounts before accumulated amortization as of the balance sheet date of all intangible assets having statutory or estimated useful lives. The aggregate gross carrying amount (including any previously recognized impairment charges) of a major finite-lived intangible asset class. A major class is composed of intangible assets that can be grouped together because they are similar, either by their nature or by their use in the operations of a company.

+ References

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- Definition

The maximum useful life of a major finite-lived intangible asset class. A major class is composed of intangible assets that can be grouped together because they are similar either by their nature or by their use in the operations of a company.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 35
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6904245&loc=d3e15217-109273

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 35
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=6904245&loc=d3e15300-109273

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 35
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6904245&loc=d3e15211-109273

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The minimum useful life of a major finite-lived intangible asset class. A major class is composed of intangible assets that can be grouped together because they are similar either by their nature or by their use in the operations of a company.

+ References

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