Summary of Significant Accounting Policies - Goodwill and Intangible Assets (Details)	12 Months Ended
Dec. 31, 2017 USD ($)
Accounting Policies [Abstract]
Goodwill and intangible asset impairment	$ 0

Total loss recognized during the period from the impairment of goodwill plus the loss recognized in the period resulting from the impairment of the carrying amount of intangible assets, other than goodwill.

No definition available.

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