Commitments and Contingencies - Leases (Details) $ in Millions	6 Months Ended
Jun. 30, 2016 USD ($) item	Jun. 30, 2015 USD ($)
Commitments and Contingencies
Number of leases that require rent to be paid based on contingent events \| item	0
Rent expense \| $	$ 13.4	$ 12.7

Rental expense for the reporting period incurred under operating leases, including minimum and any contingent rent expense, net of related sublease income.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6453985&loc=d3e41499-112717

Name:	us-gaap_OperatingLeasesRentExpenseNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration