Description of Business and Summary of Significant Accounting Policies (Finite-lived Intangible Assets) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Finite-Lived and Indefinite-Lived Intangible Assets [Line items]
Document Period End Date			Sep. 30, 2015
Finite-lived intangible assets, gross	$ 91,301		$ 91,301		$ 86,301
Finite-lived intangible assets, accumulated amortization	(41,710)		(41,710)		(36,930)
Finite-lived intangible assets, net	49,591		49,591		49,371
Amortization of Acquired Intangible Assets	1,800	$ 1,900	5,400	$ 5,600
Customer Relationships [Member]
Finite-Lived and Indefinite-Lived Intangible Assets [Line items]
Finite-lived intangible assets, gross	70,262		$ 70,262		66,783
Customer Relationships [Member] | Minimum [Member]
Finite-Lived and Indefinite-Lived Intangible Assets [Line items]
Finite-lived intangible asset, useful life			7 years
Customer Relationships [Member] | Maximum [Member]
Finite-Lived and Indefinite-Lived Intangible Assets [Line items]
Finite-lived intangible asset, useful life			20 years
Developed technology [Member]
Finite-Lived and Indefinite-Lived Intangible Assets [Line items]
Finite-lived intangible assets, gross	17,205		$ 17,205		15,664
Developed technology [Member] | Minimum [Member]
Finite-Lived and Indefinite-Lived Intangible Assets [Line items]
Finite-lived intangible asset, useful life			3 years
Developed technology [Member] | Maximum [Member]
Finite-Lived and Indefinite-Lived Intangible Assets [Line items]
Finite-lived intangible asset, useful life			12 years
Trademarks [Member]
Finite-Lived and Indefinite-Lived Intangible Assets [Line items]
Finite-lived intangible assets, gross	2,739		$ 2,739		2,751
Trademarks [Member] | Minimum [Member]
Finite-Lived and Indefinite-Lived Intangible Assets [Line items]
Finite-lived intangible asset, useful life			3 years
Trademarks [Member] | Maximum [Member]
Finite-Lived and Indefinite-Lived Intangible Assets [Line items]
Finite-lived intangible asset, useful life			15 years
Non-compete agreements [Member]
Finite-Lived and Indefinite-Lived Intangible Assets [Line items]
Finite-lived intangible assets, gross	743		$ 743		751
Non-compete agreements [Member] | Maximum [Member]
Finite-Lived and Indefinite-Lived Intangible Assets [Line items]
Finite-lived intangible asset, useful life			5 years
Backlog [Member]
Finite-Lived and Indefinite-Lived Intangible Assets [Line items]
Finite-lived intangible assets, gross	140		$ 140		140
Database [Member]
Finite-Lived and Indefinite-Lived Intangible Assets [Line items]
Finite-lived intangible assets, gross	212		$ 212		212
Database [Member] | Maximum [Member]
Finite-Lived and Indefinite-Lived Intangible Assets [Line items]
Finite-lived intangible asset, useful life			10 years
Customer Relationships [Member]
Finite-Lived and Indefinite-Lived Intangible Assets [Line items]
Indefinite-lived intangible assets	$ 30,887		$ 30,887		$ 30,887