Summary of Significant Accounting Policies - Long-term Asset Related to Jamul Tribe (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2018	Dec. 31, 2017
Loan to JIVDC
Loans to the JIVDC	$ 20,613	$ 20,900
JIVDC
Loan to JIVDC
Financing loan receivable, unpaid principal balance	98,500	98,300
Loans to the JIVDC	20,600	$ 20,900
Loans to JIVDC \| Concentration of Risk, Maximum Amount of Loss
Loan to JIVDC
Remaining exposure inclusive of future unfunded commitments	$ 27,600

An amount representing an agreement for an unconditional promise by the maker to pay the Entity (holder) a definite sum of money at a future date more than one year from the balance sheet date, net of any write-downs taken for collection uncertainty on the part of the holder. Such amount may include accrued interest receivable in accordance with the terms of the debt. The debt also may contain provisions and related items including a discount or premium, payable on demand, secured, or unsecured, interest bearing or noninterest bearing, among a myriad of other features and characteristics. This amount does not include amounts related to receivables held-for-sale.

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 210.5-02.17)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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