The maximum amount of debt and equity to be issued under the Shelf Registration.

No definition available.

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- Definition

The amount of dividend accrued attributable to share based compensation which is not yet vested.

+ References

No definition available.

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- References

No definition available.

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- Definition

Aggregate dividends declared during the period for each share of common stock outstanding.

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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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No definition available.

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Amount of paid and unpaid common stock dividends declared with the form of settlement in cash, stock and payment-in-kind (PIK).

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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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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No definition available.

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- Definition

Amount of stock repurchase plan authorized.

+ References

No definition available.

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- Definition

The number of shares authorized to be repurchased by an entity's Board of Directors under a stock repurchase plan.

+ References

No definition available.

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- Definition

The remaining number of shares authorized to be repurchased by an entity's Board of Directors under a stock repurchase plan.

+ References

No definition available.

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- Definition

Total cost of shares repurchased divided by the total number of shares repurchased.

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Number of shares that have been repurchased during the period and are being held in treasury.

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Equity, Stock Repurchase Program, Dividends, and Shelf Registration (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Aug. 31, 2018	Apr. 30, 2018	Aug. 31, 2017	May 31, 2017	Dec. 31, 1999
Dividends Payable [Line Items]
Dividends declared (in dollars per share)	$ 0.08	$ 0.08	$ 0.08
Share based compensation dividends accrued	$ 20	$ 24
Debt Instrument [Line Items]
Maximum amount of debt and equity to be issued under Shelf Registration					$ 500,000
Common Class A [Member] \| Stock Repurchase Program [Member]
Stock Repurchase Program [Abstract]
Amount of shares authorized to be repurchased								$ 9,000
Number of shares authorized to be repurchased (in shares)				610,511		425,352	500,000
Shares repurchased (in shares)	419,995	484,526	348,687
Average price per share of repurchased shares (in dollars per share)	$ 25.25	$ 29.56	$ 30.88
Share available under program to repurchase (in shares)	864,810
Common Stock Class A and Class B [Member]
Dividends Payable [Line Items]
Dividends declared (in dollars per share)	$ 0.08	$ 0.08	$ 0.08
Dividend cost	$ 2,300	$ 2,400	$ 2,400