Long-Lived Assets (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Summary of Property and Equipment
Property and equipment, gross	176,391us-gaap_PropertyPlantAndEquipmentGross	$ 164,583us-gaap_PropertyPlantAndEquipmentGross
Less—accumulated depreciation	(138,065)	(129,522)
Property and equipment, net	38,326us-gaap_PropertyPlantAndEquipmentNet	35,061us-gaap_PropertyPlantAndEquipmentNet
Computer equipment
Summary of Property and Equipment
Property and equipment, gross	96,749	89,605
Computer equipment \| Minimum
Summary of Property and Equipment
Property and equipment, useful lives	3 years
Computer equipment \| Maximum
Summary of Property and Equipment
Property and equipment, useful lives	5 years
Leasehold improvements
Summary of Property and Equipment
Property and equipment, gross	16,566	15,793
Leasehold improvements \| Minimum
Summary of Property and Equipment
Property and equipment, useful lives	5 years
Leasehold improvements \| Maximum
Summary of Property and Equipment
Property and equipment, useful lives	10 years
Operating equipment
Summary of Property and Equipment
Property and equipment, gross	55,501	48,759
Operating equipment \| Minimum
Summary of Property and Equipment
Property and equipment, useful lives	3 years
Operating equipment \| Maximum
Summary of Property and Equipment
Property and equipment, useful lives	8 years
Furniture and fixtures
Summary of Property and Equipment
Property and equipment, gross	7,531	10,426
Furniture and fixtures \| Minimum
Summary of Property and Equipment
Property and equipment, useful lives	3 years
Furniture and fixtures \| Maximum
Summary of Property and Equipment
Property and equipment, useful lives	8 years
Capital projects in process
Summary of Property and Equipment
Property and equipment, useful lives	0 years
Property and equipment, gross	44

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 360

-SubTopic 10

-Section 50

-Paragraph 1

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.14)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 14

-Article 5

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- Definition

Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 360

-SubTopic 10

-Section 50

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.13)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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- Definition

Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 360

-SubTopic 10

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.13)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 13

-Subparagraph a

-Article 5

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 8

-Article 7

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- Definition

Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

+ References

No definition available.

+ Details

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