Equity and Dividends (Schedule of Quarterly Dividends Declared and Paid) (Details) $ / shares in Units, $ in Thousands	3 Months Ended
Mar. 31, 2018 USD ($) $ / shares
Fourth Quarter 2016 [Member]
Dividends Payable [Line Items]
Declaration date	Jan. 23, 2017
Dividend per share \| $ / shares	$ 0.1700
Record date	Feb. 10, 2017
Total dividends \| $	$ 18,160
Payment date	Mar. 03, 2017
Fourth Quarter 2017 [Member]
Dividends Payable [Line Items]
Declaration date	Jan. 26, 2018
Dividend per share \| $ / shares	$ 0.1700
Record date	Feb. 16, 2018
Total dividends \| $	$ 18,246
Payment date	Mar. 09, 2018

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

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- Definition

Date the declared dividend will be paid, in CCYY-MM-DD format.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4304-108586

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- Definition

Amount of paid and unpaid cash, stock, and paid-in-kind (PIK) dividends declared, for example, but not limited to, common and preferred stock.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 405
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6957935&loc=d3e64057-112817

+ Details

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- Definition

Date the dividend to be paid was declared, in CCYY-MM-DD format.

+ References

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Date the holder must own the stock to be entitled to the dividend, in CCYY-MM-DD format.

+ References

No definition available.

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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.

+ References

No definition available.

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