Acquisitions (Details)	3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended	3 Months Ended					9 Months Ended				12 Months Ended		9 Months Ended
	Sep. 30, 2014 USD ($)	Sep. 30, 2013 USD ($)	Sep. 30, 2014 USD ($)	Sep. 30, 2013 USD ($)	Sep. 30, 2014 MSB/DQ Member [Domain] USD ($)	Mar. 31, 2014 MSB/DQ Member [Domain] USD ($)	Sep. 30, 2014 MSB/DQ Member [Domain] USD ($)	Sep. 30, 2013 PIQ Acquisition [Domain] USD ($)	Sep. 30, 2013 PIQ Acquisition [Domain] NZD	Mar. 31, 2014 Terralink [Domain] USD ($)	Mar. 31, 2014 Terralink [Domain] NZD	Sep. 30, 2014 Terralink [Domain] USD ($)	Sep. 30, 2014 Terralink [Domain] Property, Plant and Equipment [Member] USD ($)	Sep. 30, 2014 Terralink [Domain] Capital Data And Database Developement Costs [Domain] USD ($)	Sep. 30, 2014 Terralink [Domain] Trade Names [Member] USD ($)	Sep. 30, 2014 Terralink [Domain] Customer Lists [Member]	Dec. 31, 2013 EQECAT Acquisition [Member] USD ($)	Sep. 30, 2014 EQECAT Acquisition [Member] USD ($)	Sep. 30, 2014 EQECAT Acquisition [Member] Trade Names [Member]	Sep. 30, 2014 EQECAT Acquisition [Member] Customer Lists [Member]	Sep. 30, 2014 Data and analytics [Member] USD ($)	Sep. 30, 2014 Data and analytics [Member] MSB/DQ Member [Domain] USD ($)	Sep. 30, 2014 Data and analytics [Member] Terralink [Domain] USD ($)
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents																						$ 36,000
Business Combination, Acquired Receivables, Gross Contractual Amount																						9,227,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Prepaid Expense and Other Assets																						2,190,000
Business Combination, Recognized Intangible Assets Acquired, Deferred Tax Asset Current																						8,589,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment																						177,311,000
Goodwill, Acquired During Period			315,685,000				309,448,000										15,300,000				285,745,000	279,500,000	2,300,000
Business Acquisition, Purchase Price Allocation, Amortizable Intangible Assets												1,400,000	2,100,000	6,000,000	200,000			600,000				129,400,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Assets Noncurrent																						26,072,000
Business Combination, Recognized Intangible Assets Acquired, equity method investment																						18,300,000
Business Acquisition, Recognized Identifiable Assets ACquried and Liabilities Assumed, Assets																						680,573,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Accounts Payable																						3,957,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Deferred Revenue																						22,403,000
business acquisition, recognized identifiable assets acquired, deferred revenue non current																						1,663,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net																						652,519,000
Business Acquisition, Goodwill, Expected Tax Deductible Amount																						144,600,000
Goodwill, Period Increase (Decrease)					53,800,000
Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual			46,300,000
Business Acquisition, Pro Forma Revenue	385,764,000	382,797,000	1,123,908,000	1,127,719,000
Business Acquisition, Pro Forma Net Income (Loss)	44,314,000	42,689,000	63,652,000	110,055,000
Business Acquisition, Cost of Acquired Entity, Cash Paid						652,500,000		2,600,000	3,300,000	11,900,000	14,500,000						22,200,000
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life													5 years	15 years	12 years	15 years			10 years	14 years
Finite-Lived Customer Lists, Gross																		3,900,000
Business Combination, Acquisition Related Costs			$ 9,500,000