Mortgage Banking Activities (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Mortgage Banking [Abstract]
Loans originated for sale	$ 412,925	$ 598,439	$ 502,716
Proceeds from sale of loans originated for sale	425,262	619,818	509,373
Gain on loans sold	7,775	12,462	8,845
Gain (loss) resulting from the change in fair value of loans held-for-sale	638	(500)	(341)
Gain (loss) resulting from the change in fair value of derivatives	(577)	436	496
Mortgage banking activities	$ 7,836	$ 12,398	$ 9,000

Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4A
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5618551-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (a),(c),(d),(e)
-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624171-113959

+ Details

Name:	us-gaap_DerivativeGainLossOnDerivativeNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The noninterest income derived from mortgage banking activities (fees and commissions), excluding fees earned from servicing third-party assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.13 (d))
-URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882

+ Details

Name:	us-gaap_FeesAndCommissionsMortgageBanking
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The gains (losses) included in earnings that represent the difference between the sale price and the carrying value of loans and leases that were sold during the reporting period. This element refers to the gain (loss) and not to the cash proceeds of the sales. This element is a noncash adjustment to net income when calculating net cash generated by operating activities using the indirect method.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 24
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3521-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585

+ Details

Name:	us-gaap_GainLossOnSaleOfLoansAndLeases
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The increase (decrease) during the reporting period in the value of loans or securitized loans that are held with the intention to sell in the near future.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 21
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3461-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 230
-Section 55
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=82926135&loc=d3e60097-112785

+ Details

Name:	us-gaap_IncreaseDecreaseInLoansHeldForSale
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- References

No definition available.

+ Details

Name:	us-gaap_MortgageBankingAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The aggregate amount of cash outflow for loans purchased and created with the intention to resell them in the near future.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3367-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 230
-Section 55
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=82926135&loc=d3e60097-112785

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 21
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3461-108585

+ Details

Name:	us-gaap_PaymentsForOriginationAndPurchasesOfLoansHeldForSale
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The cash inflow from sales of loans that are secured with real estate mortgages and are held with the intention to resell in the near future.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 25
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3536-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 21
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3461-108585

+ Details

Name:	us-gaap_ProceedsFromSaleOfMortgageLoansHeldForSale
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration