Restricted Cash (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Restricted Cash and Cash Equivalents Items [Line Items]
Current restricted cash	$ 31,338	$ 30,256
Non-current restricted cash	14,700	14,700
Held in Trust Deposits
Restricted Cash and Cash Equivalents Items [Line Items]
Current restricted cash	23,900	25,700
Held for Advertising Activity Deposits
Restricted Cash and Cash Equivalents Items [Line Items]
Current restricted cash	$ 6,998	$ 4,300

The carrying amounts of cash and cash equivalent items which are restricted as to withdrawal or usage. Restrictions may include legally restricted deposits held as compensating balances against short-term borrowing arrangements, contracts entered into with others, or entity statements of intention with regard to particular deposits; however, time deposits and short-term certificates of deposit are not generally included in legally restricted deposits. Excludes compensating balance arrangements that are not agreements which legally restrict the use of cash amounts shown on the balance sheet. For a classified balance sheet represents the current portion only (the noncurrent portion has a separate concept); there is a separate and distinct element for unclassified presentations.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.1)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Name:	us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant