Fair Value - Assets and liabilities measured at fair value on a recurring basis - (Details) - USD ($) $ in Thousands	9 Months Ended
Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Assets
Loans held for sale	$ 57,052	$ 48,985	$ 41,649
Securities available for sale	925,374	885,798	1,009,541
Government-sponsored entities debt
Assets
Securities available for sale	62,980	123,794	162,507
State and municipal obligations
Assets
Securities available for sale	117,324	134,338	131,364
Common Stock
Assets
Securities available for sale	3,793	2,593	3,821
Significant Other Observable Inputs (Level 2)
Assets
Loans held for sale	57,052	48,985	41,649
Significant Unobservable Inputs (Level 3)
Assets
Mortgage servicing rights	23,064	24,665	26,202
Changes in fair value of assets
Changes in hierarchy classifications of Level 3 liabilities	0
Recurring basis
Assets
Derivative financial instruments	3,091	2,379	1,415
Loans held for sale	57,052	48,985	41,649
Securities available for sale	925,374	885,798	1,009,541
Mortgage servicing rights	23,064	24,665	26,202
Fair value of Assets, Total	1,008,581	961,827	1,078,807
Liabilities
Derivative financial instruments	1,100	1,904	838
Recurring basis \| Government-sponsored entities debt
Assets
Securities available for sale	62,980	123,794	162,507
Recurring basis \| State and municipal obligations
Assets
Securities available for sale	117,324	134,338	131,364
Recurring basis \| Mortgage-backed securities
Assets
Securities available for sale	741,277	625,073	711,849
Recurring basis \| Common Stock
Assets
Securities available for sale	3,793	2,593	3,821
Recurring basis \| Quoted Prices In Active Markets for Identical Assets (Level 1)
Assets
Securities available for sale	2,568	2,368	2,596
Fair value of Assets, Total	2,568	2,368	2,596
Recurring basis \| Quoted Prices In Active Markets for Identical Assets (Level 1) \| Common Stock
Assets
Securities available for sale	2,568	2,368	2,596
Recurring basis \| Significant Other Observable Inputs (Level 2)
Assets
Derivative financial instruments	3,091	2,379	1,415
Loans held for sale	57,052	48,985	41,649
Securities available for sale	922,806	883,430	1,006,945
Fair value of Assets, Total	982,949	934,794	1,050,009
Liabilities
Derivative financial instruments	1,100	1,904	838
Recurring basis \| Significant Other Observable Inputs (Level 2) \| Government-sponsored entities debt
Assets
Securities available for sale	62,980	123,794	162,507
Recurring basis \| Significant Other Observable Inputs (Level 2) \| State and municipal obligations
Assets
Securities available for sale	117,324	134,338	131,364
Recurring basis \| Significant Other Observable Inputs (Level 2) \| Mortgage-backed securities
Assets
Securities available for sale	741,277	625,073	711,849
Recurring basis \| Significant Other Observable Inputs (Level 2) \| Common Stock
Assets
Securities available for sale	1,225	225	1,225
Recurring basis \| Significant Unobservable Inputs (Level 3)
Assets
Mortgage servicing rights	23,064	24,665	26,202
Fair value of Assets, Total	23,064	24,665	$ 26,202
Changes in fair value of assets
Fair value of assets at the beginning of the period	26,202	21,601
Servicing assets that resulted from transfers of financial assets	(4,182)	(5,770)
Fair value of assets at the end of the period	23,064	24,665
Changes in fair value assets due to valuation inputs or assumptions	(4,305)	(92)
Changes in fair value assets due to increased principal paydowns	3,015	2,614
Unrealized losses included in accumulated other comprehensive income related to Level 3 financial assets and liabilities	$ 0	$ 0

No definition available.

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- Definition

Represents the amount of servicing assets that resulted from transfers of financial assets.

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No definition available.

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- Definition

The element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, the element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. The item represents residential mortgage servicing rights as presented on the statement of financial position which are due to the entity as of the balance sheet date.

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- Definition

Accumulated appreciation or loss, net of tax, in value of the total of available-for-sale securities at the end of an accounting period.

+ References

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- Definition

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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- Definition

Amount of gain (loss) recognized in the income statement for financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of settlement of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Fair value of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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- Definition

Amount of transfers of financial instrument classified as a liability into (out of) level 3 of the fair value hierarchy.

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- Definition

Fair value as of the balance sheet date of interest rate derivative assets, which includes all such derivative instruments in hedging and nonhedging relationships that are recognized as assets.

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Fair value as of the balance sheet date of interest rate derivative liabilities, which includes all such derivative instruments in hedging and nonhedging relationships that are recognized as liabilities.

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Amount, after allowance for bad debt, of loan receivables held-for-sale that are not part of a disposal group. Excludes loans and leases covered under loss sharing agreements and loans classified as debt securities.

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