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Fair Value Measurements (Other Assumptions) (Details) - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Deposits
Carrying amount of time deposits	$ 2,248,310,000	$ 2,366,413,000
Significant Unobservable Inputs (Level 3)
Loans
Carrying amount of fixed rate performing loans	1,411,272,000	1,383,836,000
Estimated fair value of fixed rate performing loans	1,375,807,000	1,362,248,000
Deposits
Carrying amount of time deposits	2,248,310,000	2,366,413,000
Estimated fair value of time deposits	2,247,648,000	2,365,390,000
Securities Sold Under Repurchase Agreements
Carrying amount of long-term repurchase agreements	300,000,000	560,000,000
Estimated fair value of long-term repurchase agreements	$ 289,324,000	$ 527,198,600

X

- Definition

Represents the portion of fixed rate performing loans valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Fixed rate loan represents loans charging borrowers fixed rates of interest.

+ References

No definition available.

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X

- Definition

The carrying value as of the balance sheet date of securities that an institution sells and agrees to repurchase under a long term agreement (the identical or substantially the same securities) as a seller-borrower at a specified date for a specified price, also known as a repurchase agreement.

+ References

No definition available.

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X

- Definition

Represents the portion of time deposits valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Time deposits include certificates of deposits, individual retirement accounts and open accounts.

+ References

No definition available.

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- References

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X

- Definition

Amount of loan with fixed rate of interest.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=65884687&loc=d3e4428-111522

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- Definition

Fair value portion of securities that an entity sells and agrees to repurchase at a specified date for a specified price.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=73719730&loc=d3e13433-108611

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- Definition

Amount of time deposit liabilities, including certificates of deposit.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 405
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=50488274&loc=d3e64164-112818

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.12)
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Industry Guide
-Number 3
-Section V
-Paragraph D-E

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