Significant Accounting Policies - Goodwill and Indefinite-Lived Intangible Assets (Details)	9 Months Ended
Sep. 30, 2017 USD ($)
New York Code And Design Academy, Inc.
Goodwill and Indefinite-Lived Intangible Assets
Goodwill and intangible assets 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