Loans and Allowance for Credit Losses - Detail activity in the allowance for credit losses by portfolio segment (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Allowance for Credit Losses, beginning balance	$ 108,796	$ 72,086	$ 73,658	$ 69,944
Impact of adopting ASC 326	(10,931)		(10,931)		$ 10,614
Loans charged-off	(5,228)	(1,794)	(14,691)	(7,144)
Allowance for Loan and Lease Loss, Recovery of Bad Debts	58	242	136	774
Net loans (charged-off) recoveries	(5,170)	(1,552)	(14,555)	(6,370)
Provision for Loan and Lease Losses	6,589	3,186	40,498	10,146
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	17,617	10,434	17,617	10,434
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	92,598	63,286	92,598	63,286
Allowance for Credit Losses, ending balance	110,215	73,720	110,215	73,720
Commercial
Allowance for Credit Losses, beginning balance	28,078	18,136	18,832	15,857
Impact of adopting ASC 326					892
Loans charged-off	(187)	(1,794)	(7,332)	(1,799)
Allowance for Loan and Lease Loss, Recovery of Bad Debts	45	210	116	377
Net loans (charged-off) recoveries	(142)	(1,584)	(7,216)	(1,422)
Provision for Loan and Lease Losses	(712)	1,617	14,716	3,734
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	9,593	8,196	9,593	8,196
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	17,631	9,973	17,631	9,973
Allowance for Credit Losses, ending balance	27,224	18,169	27,224	18,169
Income producing - commercial real estate
Allowance for Credit Losses, beginning balance	51,863	27,010	29,265	28,034
Impact of adopting ASC 326					11,230
Loans charged-off	(3,750)		(4,300)	(5,343)
Allowance for Loan and Lease Loss, Recovery of Bad Debts				302
Net loans (charged-off) recoveries	(3,750)	0	(4,300)	(5,041)
Provision for Loan and Lease Losses	7,327	1,517	19,245	5,534
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	5,999	1,200	5,999	1,200
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	49,441	27,327	49,441	27,327
Allowance for Credit Losses, ending balance	55,440	28,527	55,440	28,527
Owner occupied - Commercial real estate
Allowance for Credit Losses, beginning balance	12,341	5,756	5,838	6,242
Impact of adopting ASC 326					4,674
Loans charged-off	(20)		(20)
Allowance for Loan and Lease Loss, Recovery of Bad Debts				2
Net loans (charged-off) recoveries	(20)	0	(20)	2
Provision for Loan and Lease Losses	769	(158)	2,598	(646)
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	670	375	670	375
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	12,420	5,223	12,420	5,223
Allowance for Credit Losses, ending balance	13,090	5,598	13,090	5,598
Real estate mortgage residential
Allowance for Credit Losses, beginning balance	1,550	1,355	1,557	965
Impact of adopting ASC 326					(301)
Allowance for Loan and Lease Loss, Recovery of Bad Debts				3
Net loans (charged-off) recoveries		0		3
Provision for Loan and Lease Losses	321	(3)	615	384
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	1,148	650	1,148	650
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	723	702	723	702
Allowance for Credit Losses, ending balance	1,871	1,352	1,871	1,352
Construction - commercial and residential
Allowance for Credit Losses, beginning balance	13,808	19,006	17,485	18,175
Impact of adopting ASC 326					(6,143)
Loans charged-off	(1,179)		(2,947)
Allowance for Loan and Lease Loss, Recovery of Bad Debts		15		52
Net loans (charged-off) recoveries	1,179	15	(2,947)	52
Provision for Loan and Lease Losses	(1,088)	251	3,146	1,045
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	204	0	204	0
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	11,337	19,272	11,337	19,272
Allowance for Credit Losses, ending balance	11,541	19,272	11,541	19,272
Home equity
Allowance for Credit Losses, beginning balance	1,112	581	656	599
Impact of adopting ASC 326					245
Loans charged-off	(92)		(92)
Net loans (charged-off) recoveries	(92)		(92)
Provision for Loan and Lease Losses	(13)	(6)	198	(24)
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		13		13
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	1,007	562	1,007	562
Allowance for Credit Losses, ending balance	1,007	575	1,007	575
Other consumer
Allowance for Credit Losses, beginning balance	44	242	25	72
Impact of adopting ASC 326					$ 17
Loans charged-off				(2)
Allowance for Loan and Lease Loss, Recovery of Bad Debts	13	17	20	38
Net loans (charged-off) recoveries	13	17	20	36
Provision for Loan and Lease Losses	(15)	(32)	(20)	119
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	3	0	3	0
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	39	227	39	227
Allowance for Credit Losses, ending balance	$ 42	$ 227	$ 42	$ 227

Amount of recovery of loans and lease receivables which had previously been fully or partially written-off as bad debts.

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Amount of loans and leases that have been written off from both loan receivables and allowance reserve for credit loss.

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Amount, after recoveries, of loans and leases that have been written-off.

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Amount after tax of increase (decrease) to equity or (increase) decrease to net assets, resulting from the cumulative effect adjustment of a new accounting principle applied in the period of adoption.

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The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment.

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Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

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Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

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Amount of expense related to estimated loss from loan and lease transactions.

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