Equity Securities at Fair Value (Detail) $ in Thousands	Jun. 30, 2018 USD ($)
Gain (Loss) on Investments [Line Items]
Fair Value	$ 327,466
Gross Unrealized Gains	13,603
Gross Unrealized (Losses)	(3,634)
Cost	317,497
Common Stock
Gain (Loss) on Investments [Line Items]
Fair Value	145,077
Gross Unrealized Gains	9,749
Gross Unrealized (Losses)	(499)
Cost	135,827
Preferred Stocks
Gain (Loss) on Investments [Line Items]
Fair Value	182,389
Gross Unrealized Gains	3,854
Gross Unrealized (Losses)	(3,135)
Cost	$ 181,670

Amount before tax of accumulated unrealized gain on Equity Securities.

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- Definition

Amount before tax of accumulated unrealized loss on Equity Securities.

+ References

No definition available.

+ Details

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- Definition

Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 45
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=99377092&loc=SL75136599-209740

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Cost of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI). Excludes equity method investment and investment in equity security without readily determinable fair value.

+ References

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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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