Equity Securities at Fair Value (Detail) $ in Thousands	Sep. 30, 2018 USD ($)
Gain (Loss) on Investments [Line Items]
Fair Value	$ 371,680
Gross Unrealized Gains	17,474
Gross Unrealized (Losses)	(5,194)
Cost	359,400
Common Stock
Gain (Loss) on Investments [Line Items]
Fair Value	190,722
Gross Unrealized Gains	15,573
Gross Unrealized (Losses)	(116)
Cost	175,265
Preferred Stocks
Gain (Loss) on Investments [Line Items]
Fair Value	180,958
Gross Unrealized Gains	1,901
Gross Unrealized (Losses)	(5,078)
Cost	$ 184,135

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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- Definition

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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