Commitments and Contingencies Commitments and Contingencies (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
Sep. 30, 2013 sqft Y	Sep. 30, 2004
Long-term Purchase Commitment [Line Items]
Minimum remaining lease period	16
Maximum remaining lease period	90
Leased Area Of Building	708,844
Business Combination, Future Expected Libaility	$ 2.9
Business Acquisition, Cost of Acquired Entity, Liabilities Incurred	$ 1.6	$ 0.7

Amount of liabilities incurred by the acquirer as part of consideration transferred in a business combination.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 30

-Section 25

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=6911189&loc=d3e6405-128476

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 30

-Section 30

-Paragraph 7

-URI http://asc.fasb.org/extlink&oid=6911251&loc=d3e6578-128477

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 30

-Section 30

-Paragraph 8

-URI http://asc.fasb.org/extlink&oid=6911251&loc=d3e6613-128477

Name:	us-gaap_BusinessCombinationConsiderationTransferredLiabilitiesIncurred
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration