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

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-Section 50

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- Definition

The current period expense charged against earnings on long-lived, physical assets not used in production, and which are not intended for resale, to allocate or recognize the cost of such assets over their useful lives; or to record the reduction in book value of an intangible asset over the benefit period of such asset; or to reflect consumption during the period of an asset that is not used in production.

+ References

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

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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

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-Name Accounting Standards Codification

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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

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Property and Equipment, Net (Details) (USD $)	12 Months Ended
Property and Equipment, Net (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 529,294,000us-gaap_PropertyPlantAndEquipmentGross	$ 502,104,000us-gaap_PropertyPlantAndEquipmentGross
Accumulated depreciation	(334,454,000)	(297,962,000)
Property and equipment, net	194,840,000us-gaap_PropertyPlantAndEquipmentNet	204,142,000us-gaap_PropertyPlantAndEquipmentNet
Depreciation expense	49,200,000us-gaap_DepreciationAndAmortization	42,600,000us-gaap_DepreciationAndAmortization	32,900,000us-gaap_DepreciationAndAmortization
Land and land rights [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	23,157,000	23,157,000
Building [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	161,070,000	159,123,000
Equipment and software [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	298,069,000	281,197,000
Office furniture and fixtures [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	24,601,000	24,438,000
Leasehold improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	12,800,000	12,391,000
Construction in progress [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 9,597,000	$ 1,798,000