Fair Value Measurements (Balance Measured at Fair Value) (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Current		$ 400
Assets
Restricted cash	$ 26,705	16,488
Investment available for sale	17,300	16,800
Liabilities
Fair Value, Discount Amount, Available for sales securities	3,000	3,100
Fair Value, Measurements, Recurring [Member]
Assets
Cash and cash equivalents	158,832	193,862
Restricted cash	26,705	16,488
Investment available for sale	17,823	17,259	$ 20,500
Liabilities
Business Combination, Contingent Consideration, Liability	3,019	3,038
Fair Value, Measurements, Recurring [Member] \| Level 1
Assets
Cash and cash equivalents	158,832	193,862
Investment available for sale	0	0
Liabilities
Business Combination, Contingent Consideration, Liability	0	0
Fair Value, Measurements, Recurring [Member] \| Level 2
Assets
Cash and cash equivalents	0	0
Restricted cash	0	0
Investment available for sale	0	0
Liabilities
Business Combination, Contingent Consideration, Liability	0	0
Fair Value, Measurements, Recurring [Member] \| Level 3
Assets
Cash and cash equivalents	0	0
Restricted cash	0	0
Investment available for sale	17,823	17,259
Liabilities
Business Combination, Contingent Consideration, Liability	3,019	3,038
Peninsula Gaming [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Current	$ 500	$ 400

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Cash and Cash Equivalents, Restricted, Fair Value Disclosure

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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Amount of investment in debt and equity securities categorized neither as trading securities nor held-to-maturity securities and intended be sold or mature one year or operating cycle, if longer.

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Amount of liability recognized arising from contingent consideration in a business combination.

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Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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