Intangible Assets (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 157,338,000	$ 155,735,000
Accumulated Amortization	107,225,000	94,556,000
Total	50,113,000	61,179,000
Amortization expense	12,700,000	12,600,000	13,400,000
Estimated future amortization expense [Abstract]
2014	11,170,000
2015	6,783,000
2016	5,003,000
2017	3,343,000
2018	3,307,000
2019 and thereafter	20,507,000
Total	50,113,000	61,179,000
Intangible assets not subject to amortization	29,000,000	29,000,000	29,000,000
Indefinite-lived intangible asset impairment loss			900,000
Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful life	2 years
Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful life	25 years
Customer Contracts [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	59,574,000	59,305,000
Accumulated Amortization	51,512,000	44,571,000
Total	8,062,000	14,734,000
Estimated future amortization expense [Abstract]
Total	8,062,000	14,734,000
Acquired Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	29,431,000	29,287,000
Accumulated Amortization	25,589,000	24,299,000
Total	3,842,000	4,988,000
Estimated future amortization expense [Abstract]
Total	3,842,000	4,988,000
Patents [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	24,547,000	24,337,000
Accumulated Amortization	15,081,000	12,723,000
Total	9,466,000	11,614,000
Estimated future amortization expense [Abstract]
Total	9,466,000	11,614,000
Distributor and Provider Networks [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	8,709,000	8,709,000
Accumulated Amortization	7,190,000	6,669,000
Total	1,519,000	2,040,000
Estimated future amortization expense [Abstract]
Total	1,519,000	2,040,000
Perpetual License to Survey-Based Data [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	30,000,000	29,000,000
Accumulated Amortization	3,986,000	2,708,000
Total	26,014,000	26,292,000
Estimated future amortization expense [Abstract]
Total	26,014,000	26,292,000
Other [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	5,077,000	5,097,000
Accumulated Amortization	3,867,000	3,586,000
Total	1,210,000	1,511,000
Estimated future amortization expense [Abstract]
Total	$ 1,210,000	$ 1,511,000