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Investment Securities - Securities Sold, Pledged as Collateral and Transfers (Details) - USD ($) $ in Thousands		3 Months Ended
	Feb. 24, 2017	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Held-to-maturity Securities, Sales, Excluding Other than Temporary Impairments [Abstract]
Sales proceeds		$ 0	$ 54,985
Gross realized gains		0	110
Gross realized losses		0	0
Available-for-sale:
Securities transferred from available-for-sale to held-to-maturity	$ 129,000	128,965	$ 0
Unrealized pre-tax loss from transfer of available-for-sale securities to held-to-maturity	$ 3,000
State of California
Available-for-sale:
Available-for-sale securities pledged as collateral		103,600		$ 109,100
Public Deposits
Available-for-sale:
Available-for-sale securities pledged as collateral		102,800		108,300
Trust Deposits
Available-for-sale:
Available-for-sale securities pledged as collateral		819		$ 822
Internal checking account
Available-for-sale:
Available-for-sale securities pledged as collateral		$ 2,100

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- Definition

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+ References

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- Definition

Available-for-sale Securities, Transferred to Held-to-maturity Securities, Unrealized Gain (Loss)

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- Definition

Held-To-Maturity Securities, Sold Security, Realized Gain

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- Definition

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- Definition

Sum of the carrying amounts as of the date of the latest financial statement presented of securities which are owned but transferred to another party to serve as collateral to partially or fully secure a debt obligation, repurchase agreement or other current or potential obligation, and for which the transferee is not permitted to sell or re-pledge them to an unrelated party.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 30
-Section 50
-Paragraph 1A
-Subparagraph (b)(1)(i)
-URI http://asc.fasb.org/extlink&oid=64858031&loc=SL6224234-111729

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- Definition

The cash inflow associated with the sale of securities that had been designated as held-to-maturity. Excludes proceeds from maturities, prepayments and calls by the issuer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Investing Activities
-URI http://asc.fasb.org/extlink&oid=6516133

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=66010992&loc=d3e26853-111562

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3179-108585

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