Amount of realized gain on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 9
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27357-111563

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- Definition

Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258

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- Definition

The number of shares issued or sold by the subsidiary or equity method investee per stock transaction.

+ References

No definition available.

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- Definition

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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- Definition

Number of shares issued which are neither cancelled nor held in the treasury.

+ References

No definition available.

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Securities - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Securities - Narrative (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2018	Dec. 31, 2017
Debt Securities, Available-for-sale [Line Items]
Realized gain		$ 3,572	$ 0
Common Class B [Member]
Debt Securities, Available-for-sale [Line Items]
Number of shares sold	25,702
Common Class B [Member] \| Visa Inc's Initial Public Offering [Member]
Debt Securities, Available-for-sale [Line Items]
Number of shares sold		51,404
Number of shares remaining	25,702	25,702
Other investments \| Fair Value, Measurements, Nonrecurring [Member]
Debt Securities, Available-for-sale [Line Items]
Other investments	$ 3,427	$ 3,427
Fair Value, Inputs, Level 3 [Member] \| Other investments \| Fair Value, Measurements, Nonrecurring [Member]
Debt Securities, Available-for-sale [Line Items]
Other investments	$ 3,400	$ 3,400