Deposits (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Deposits, by Type [Abstract]
Noninterest-bearing demand	$ 1,591,661,000	$ 1,227,768,000
Interest-bearing demand	1,428,941,000us-gaap_DemandDepositAccounts	1,169,076,000us-gaap_DemandDepositAccounts
Savings	1,720,422,000us-gaap_DepositsSavingsDeposits	1,393,610,000us-gaap_DepositsSavingsDeposits
Time deposits over $100,000	557,476,000us-gaap_TimeDeposits100000OrMore	529,265,000us-gaap_TimeDeposits100000OrMore
Other time deposits	780,471,000us-gaap_TimeDepositsLessThan100000	802,666,000us-gaap_TimeDepositsLessThan100000
Total deposits	6,078,971,000us-gaap_Deposits	5,122,385,000us-gaap_Deposits
Maturities of Time Deposits [Abstract]
Time deposit maturities, one year or less	921,000,000us-gaap_TimeDepositMaturitiesYearOne
Time deposits maturities, after next twelve months	417,000,000us-gaap_TimeDepositsNoncurrent
Time deposit maturities, 2015	174,000,000us-gaap_TimeDepositMaturitiesYearTwo
Time deposit maturities, 2016	115,000,000us-gaap_TimeDepositMaturitiesYearThree
Time deposit maturities, 2017	59,000,000us-gaap_TimeDepositMaturitiesYearFour
Time deposit maturities, 2018	68,000,000us-gaap_TimeDepositMaturitiesYearFive
Demand deposit overdrafts	$ 4,300,000	$ 3,300,000

The amount of money in accounts that may bear interest and that the depositor is entitled to withdraw at any time without prior notice.

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- Definition

Amount of deposits held by the entity that have been reclassified as loan balances receivable, for example, but not limited to, overdrafts receivable.

+ References

+ Details

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- Definition

The aggregate of all deposit liabilities held by the entity, including foreign and domestic, interest and noninterest bearing; may include demand deposits, saving deposits, Negotiable Order of Withdrawal (NOW) and time deposits among others.

+ References

Reference 1: 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 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 12

-Article 9

+ Details

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- Details

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- Definition

Amount of interest bearing deposits with no stated maturity, which may include passbook and statement savings accounts and money-market deposit accounts (MMDAs).

+ References

+ Details

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- Details

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- Definition

The aggregate amount of all domestic and foreign noninterest-bearing deposits liabilities held by the entity.

+ References

+ Details

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- Definition

Amount of time deposits maturing in the fifth fiscal year following the latest fiscal year. Time deposits include, but are not limited to, certificates of deposits. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 470

-SubTopic 10

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6802200&loc=d3e1835-112601

+ Details

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- Definition

Amount of time deposits maturing in the fourth fiscal year following the latest fiscal year. Time deposits include, but are not limited to, certificates of deposits. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

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- Definition

Amount of time deposits maturing in the next fiscal year following the latest fiscal year. Time deposits include, but are not limited to, certificates of deposits. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

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- Definition

Amount of time deposits maturing in the third fiscal year following the latest fiscal year. Time deposits include, but are not limited to, certificates of deposits. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

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- Definition

Amount of time deposits maturing in the second fiscal year following the latest fiscal year. Time deposits include, but are not limited to, certificates of deposits. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

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- Definition

The aggregate amount of domestic and foreign time deposit liabilities (including certificates of deposits, individual retirement accounts and open accounts) in denominations of $100,000 or more.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 405

-Section 50

-Paragraph 1

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6479006&loc=d3e64164-112818

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Industry Guide

-Number 3

-Section V

-Paragraph A

-Subparagraph 4

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- Definition

The aggregate amount of domestic or foreign time deposits (including certificates of deposits, individual retirement accounts and open accounts) that total to less than $100,000.

+ References

No definition available.

+ Details

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- Definition

Amount of time deposits maturing after the next fiscal year following the latest fiscal year. Time deposits include, but are not limited to, certificates of deposits. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ 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=6479006&loc=d3e64164-112818

+ Details

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