Nominal or face amount used to calculate payments on the derivative asset.

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Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

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Fixed interest rate related to the interest rate derivative.

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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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The amount of net gains or losses on interest rate cash flow hedges reclassified during the period to earnings from accumulated other comprehensive income upon the hedged transaction affecting earnings.

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The estimated net amount of unrealized gains or losses on interest rate cash flow hedges as of the balance sheet date expected to be reclassified to earnings within the next twelve months.

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Number of interest rate derivative instruments held by the entity at the reporting date.

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Amount after tax and reclassification adjustments of other comprehensive income (loss).

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Amount of long-term notes payable classified as other.

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Fair Value Of Financial Instruments (Details) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2018 USD ($) agreement	Sep. 30, 2018 USD ($) agreement	Dec. 31, 2017 USD ($)
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Interest rate cash flow hedge to be reclassified within next 12 months, net	$ 100	$ 100
(Decrease) increase in our derivative asset (less than for equity method investees)		105
Interest expense reclassified from other comprehensive income	200	300
Accumulated other comprehensive income
Fair Value, Balance Sheet Grouping, Financial Statement Captions
(Decrease) increase in our derivative asset (less than for equity method investees)		105
Accumulated other comprehensive income \| One of our equity method investees
Fair Value, Balance Sheet Grouping, Financial Statement Captions
(Decrease) increase in our derivative asset (less than for equity method investees)	100	100
Term loan \| Accumulated other comprehensive income
Fair Value, Balance Sheet Grouping, Financial Statement Captions
(Decrease) increase in our derivative asset (less than for equity method investees)	(300)	100
Fair Value, Measurements, Recurring \| Prepaid expenses and other assets
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Fair value of interest rate swaps	100	100
Interest Rate Swap \| Term loan
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Term loan	$ 275,000	$ 275,000
Interest rate of variable portion of term loan	1.72%	1.72%
Interest Rate Swap \| Fair Value, Measurements, Recurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Number of interest rate swap agreements \| agreement	2	2
Notional amount of interest rate swap agreements	$ 275,000	$ 275,000
Fair value of interest rate swaps	$ 133	$ 133	$ 22
Interest Rate Swap \| Fair Value, Measurements, Recurring \| One of our equity method investees
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Number of interest rate swap agreements \| agreement	2	2
Interest Rate Swap \| Fair Value, Measurements, Recurring \| Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Fair value of interest rate swaps	$ 133	$ 133	$ 22