Guarantees and Other Commitments and Contingencies Lease Guarantees (Details) $ in Thousands	Dec. 31, 2017 USD ($)
Property Lease Guarantee
Guarantor Obligations
Guarantor Obligations, Maximum Exposure, Undiscounted	$ 59,901
Indirect Guarantee of Indebtedness
Guarantor Obligations
Guarantor Obligations, Maximum Exposure, Undiscounted	$ 464

Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=6851643&loc=d3e12069-110248

Name:	us-gaap_GuaranteeObligationsMaximumExposure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant