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Consolidated Statements Of Changes In Shareholders' Equity (Parenthetical) - $ / shares	6 Months Ended		12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Common stock dividends per share, declared	$ 0.48	$ 0.42
Series A 3% Preferred Stock [Member]
Preferred stock, dividend percentage	3.00%	3.00%	3.00%
Preferred stock dividends per share, declared	$ 1.50	$ 1.50
Series B-1 8.48% Preferred Stock [Member]
Preferred stock, dividend percentage	8.48%	8.48%	8.48%
Preferred stock dividends per share, declared	$ 4.24	$ 4.24

X

- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-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

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- Definition

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+ References

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- Definition

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

+ References

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