Fair Value of Assets and Liabilities - Summary Of Changes In Level 3 Assets And Liabilities Measured At Fair Value (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance, net derivative	$ (5,645)	$ (6,245)	$ (4,810)
Total net gains/(losses) included in: Net Income, net derivatives	(4,677)	(596)	(2,634)
Purchases, net derivatives	(28,100)	0	0
Sales, net derivatives	0	0	0
Settlements, net derivatives	6,882	1,196	1,199
Net transfers in/(out) level 3, net derivatives	0	0	0
Ending balance, net derivative	(31,540)	(5,645)	(6,245)
Net unrealized gains/(losses) included in net income	(4,677)	(596)	(2,634)
Trading securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance, assets	2,151	2,573	4,377
Total net gains/(losses) included in : Net income, assets	173	448	604
Purchases, assets	0	0	0
Sales, assets	0	(5)	0
Settlements, assets	(800)	(865)	(2,408)
Net transfers into/(out of) Level 3, assets	0	0	0
Ending balance, assets	1,524	2,151	2,573
Net unrealized gains/(losses) included in net income	6	303	159
SBA - interest only strips
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance, assets	1,270	0
Total net gains/(losses) included in : Net income, assets	(398)	1,021
Purchases, assets	0	1,413
Sales, assets	(16,840)	(11,431)
Settlements, assets	0	0
Net transfers into/(out of) Level 3, assets	25,870	10,267
Ending balance, assets	9,902	1,270	0
Net unrealized gains/(losses) included in net income	(1,025)	(171)
Loans Held For Sale
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance, assets	18,926	21,924	27,418
Total net gains/(losses) included in : Net income, assets	1,239	1,547	3,380
Purchases, assets	62	168	706
Sales, assets	0	0	0
Settlements, assets	(3,598)	(4,346)	(6,264)
Net transfers into/(out of) Level 3, assets	(356)	(367)	(3,316)
Ending balance, assets	16,273	18,926	21,924
Net unrealized gains/(losses) included in net income	$ 1,239	1,547	3,380
Securities available- for-sale
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance, assets		0	1,500
Total net gains/(losses) included in : Net income, assets			0
Purchases, assets			0
Sales, assets			0
Settlements, assets			(1,500)
Net transfers into/(out of) Level 3, assets			0
Ending balance, assets			0
Net unrealized gains/(losses) included in net income			0
Mortgage servicing rights, net
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance, assets		$ 985	1,841
Total net gains/(losses) included in : Net income, assets			31
Purchases, assets			0
Sales, assets			(205)
Settlements, assets			(682)
Net transfers into/(out of) Level 3, assets			0
Ending balance, assets			985
Net unrealized gains/(losses) included in net income			$ 0

Amount of unrealized (holding) gain (loss) which is included in the statement of income (or changes in net assets) related to those assets still held at the reporting date for which fair value is measured on a recurring basis using significant unobservable inputs (Level 3).

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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 purchases 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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Amount of sale 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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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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Amount of transfer of financial instrument classified as an asset into (out of) level 3 of the fair value hierarchy.

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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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Amount of unrealized gain (loss) recognized in the income statement for a financial instrument classified as derivative asset (liability) after deduction of derivative liability (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 gain (loss) recognized in the income statement of financial instrument classified as a derivative asset (liability) after deduction of derivative liability (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 purchases of financial instrument classified as a derivative asset (liability) after deduction of derivative liability (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 sales of financial instrument classified as a derivative asset (liability) after deduction of derivative liability (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 settlements of financial instrument classified as a derivative asset (liability) after deduction of derivative liability, 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 transfers of financial instrument classified as a derivative asset (liability) after deduction of derivative liability (asset) into (out of) level 3 of the fair value hierarchy.

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Fair value of financial instrument classified as derivative asset (liability) after deduction of derivative liability (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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