Fair Value - Assets and liabilities measured at fair value on a recurring basis (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Assets
Derivative financial instruments	$ 51,200	$ 6,700
Securities available for sale	1,971,195	1,466,249	$ 1,956,047
Liabilities
Derivative financial instruments	54,400	7,300
Government-sponsored entities debt
Assets
Securities available for sale	4,921	65,704	25,941
State and municipal obligations
Assets
Securities available for sale	221,604	193,418	208,415
Significant Other Observable Inputs (Level 2)
Assets
Loans held for sale		33,297
Significant Unobservable Inputs (Level 3)
Assets
Mortgage servicing rights	26,365	32,415	30,525
Changes in fair value of assets
Changes in hierarchy classifications of Level 3 liabilities	0
Recurring basis
Assets
Derivative financial instruments	61,153	8,727	16,252
Loans held for sale	71,719	33,297	59,363
Securities available for sale	1,971,195	1,466,249	1,956,047
Mortgage servicing rights	26,365	32,415	30,525
Fair value of Assets, Total	2,130,432	1,540,688	2,062,187
Liabilities
Derivative financial instruments	97,861	10,330	31,273
Recurring basis \| Government-sponsored entities debt
Assets
Securities available for sale	4,921	65,704	25,941
Recurring basis \| State and municipal obligations
Assets
Securities available for sale	221,604	193,418	208,415
Recurring basis \| Mortgage-backed securities
Assets
Securities available for sale	1,744,670	1,207,127	1,721,691
Recurring basis \| Significant Other Observable Inputs (Level 2)
Assets
Derivative financial instruments	61,153	8,727	16,252
Loans held for sale	71,719	33,297	59,363
Securities available for sale	1,971,195	1,466,249	1,956,047
Fair value of Assets, Total	2,104,067	1,508,273	2,031,662
Liabilities
Derivative financial instruments	97,861	10,330	31,273
Recurring basis \| Significant Other Observable Inputs (Level 2) \| Government-sponsored entities debt
Assets
Securities available for sale	4,921	65,704	25,941
Recurring basis \| Significant Other Observable Inputs (Level 2) \| State and municipal obligations
Assets
Securities available for sale	221,604	193,418	208,415
Recurring basis \| Significant Other Observable Inputs (Level 2) \| Mortgage-backed securities
Assets
Securities available for sale	1,744,670	1,207,127	1,721,691
Recurring basis \| Significant Unobservable Inputs (Level 3)
Assets
Mortgage servicing rights	26,365	32,415	30,525
Fair value of Assets, Total	26,365	32,415	$ 30,525
Changes in fair value of assets
Fair value of assets at the beginning of the period	30,525	34,727
Servicing assets that resulted from transfers of financial assets	1,963	931
Changes in fair value assets due to valuation inputs or assumptions	(4,919)	(2,357)
Changes in fair value due to decay	1,204	886
Fair value of assets at the end of the period	26,365	32,415
Unrealized losses included in accumulated other comprehensive income related to Level 3 financial assets and liabilities	$ 0	$ 0

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

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.

+ References

No definition available.

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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.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

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- References

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- Definition

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

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- Definition

Amount of gain (loss) recognized in income from asset measured at fair value on recurring basis using unobservable input (level 3).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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- Definition

Amount of gain (loss) recognized in other comprehensive income (OCI) from asset measured at fair value on recurring basis using unobservable input (level 3).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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-SubTopic 10
-Section 50
-Paragraph 2
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-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

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- Definition

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.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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-Topic 820
-SubTopic 10
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- Definition

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.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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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.

+ References

No definition available.

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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.

+ References

No definition available.

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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.

+ References

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- Definition

Fair value portion of loans held-for-sale including, but not limited to, mortgage loans and finance receivables.

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