Loans and Allowance for Loan Losses (Allowance for Loan Losses by Portfolio Class) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Beginning balance			$ 194,514	$ 217,308
Allowance for loan losses: Net provision for loan losses	$ 12,421	$ 6,872	38,552	28,016
Reduction as a result of sale of subsidiary				(6,648)
Allowance for loan losses: Ending balance	195,572	214,550	195,572	214,550
Allowance for loan losses: Individually evaluated for impairment	12,218	23,906	12,218	23,906
Allowance for loan losses: Amounts related to purchased credit impaired loans	8,823	11,408	8,823	11,408
Allowance for loan losses: Collectively evaluated for impairment	174,531	179,236	174,531	179,236
Loans: Individually evaluated for impairment	225,138	307,081	225,138	307,081
Loans: Purchased credit impaired loans	228,620	135,035	228,620	135,035
Loans: Collectively evaluated for impairment	20,582,194	19,101,601	20,582,194	19,101,601
Loans receivable	21,035,952	19,543,717	21,035,952	19,543,717	$ 20,026,411
Non-Purchased Credit Impaired Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs			(47,365)	(43,813)
Allowance for loan losses: Recoveries			9,871	19,687
Allowance for loan losses: Net provision for loan losses			38,552	28,016
Total Commercial [Member] \| Commercial Real Estate - Income Producing [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Beginning balance			17,638	13,709
Allowance for loan losses: Ending balance	25,750	18,585	25,750	18,585
Allowance for loan losses: Individually evaluated for impairment	49	285	49	285
Allowance for loan losses: Amounts related to purchased credit impaired loans	40	45	40	45
Allowance for loan losses: Collectively evaluated for impairment	25,661	18,255	25,661	18,255
Loans: Individually evaluated for impairment	2,781	4,615	2,781	4,615
Loans: Purchased credit impaired loans	27,281	3,790	27,281	3,790
Loans: Collectively evaluated for impairment	3,030,506	2,303,294	3,030,506	2,303,294
Loans receivable	3,060,568	2,311,699	3,060,568	2,311,699	2,341,779
Total Commercial [Member] \| Construction and Land Development [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Beginning balance			15,647	7,372
Allowance for loan losses: Ending balance	9,766	13,423	9,766	13,423
Allowance for loan losses: Individually evaluated for impairment	29	1	29	1
Allowance for loan losses: Amounts related to purchased credit impaired loans	144	91	144	91
Allowance for loan losses: Collectively evaluated for impairment	9,593	13,331	9,593	13,331
Loans: Individually evaluated for impairment	3,385	112	3,385	112
Loans: Purchased credit impaired loans	23,431	4,232	23,431	4,232
Loans: Collectively evaluated for impairment	1,163,902	1,519,075	1,163,902	1,519,075
Loans receivable	1,190,718	1,523,419	1,190,718	1,523,419	1,548,335
Total Commercial [Member] \| Non-Purchased Credit Impaired Loans [Member] \| Commercial Real Estate - Income Producing [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs			(10)	(1,633)
Allowance for loan losses: Recoveries			518	221
Allowance for loan losses: Net provision for loan losses			7,604	6,288
Total Commercial [Member] \| Non-Purchased Credit Impaired Loans [Member] \| Construction and Land Development [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs			(7)	(265)
Allowance for loan losses: Recoveries			108	68
Allowance for loan losses: Net provision for loan losses			(5,982)	6,248
Total Commercial [Member] \| Total Commercial And Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Beginning balance			111,509	140,880
Allowance for loan losses: Ending balance	113,748	133,795	113,748	133,795
Allowance for loan losses: Individually evaluated for impairment	11,592	23,326	11,592	23,326
Allowance for loan losses: Amounts related to purchased credit impaired loans	307	730	307	730
Allowance for loan losses: Collectively evaluated for impairment	101,849	109,739	101,849	109,739
Loans: Individually evaluated for impairment	213,088	298,403	213,088	298,403
Loans: Purchased credit impaired loans	78,164	15,020	78,164	15,020
Loans: Collectively evaluated for impairment	11,336,131	10,425,732	11,336,131	10,425,732
Loans receivable	11,627,383	10,739,155	11,627,383	10,739,155	11,078,349
Total Commercial [Member] \| Total Commercial And Industrial [Member] \| Commercial Non-Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Beginning balance			97,752	127,918
Allowance for loan losses: Ending balance	99,299	120,678	99,299	120,678
Allowance for loan losses: Individually evaluated for impairment	11,535	23,101	11,535	23,101
Allowance for loan losses: Amounts related to purchased credit impaired loans	135	327	135	327
Allowance for loan losses: Collectively evaluated for impairment	87,629	97,250	87,629	97,250
Loans: Individually evaluated for impairment	201,979	275,966	201,979	275,966
Loans: Purchased credit impaired loans	33,040	7,907	33,040	7,907
Loans: Collectively evaluated for impairment	8,657,985	8,155,011	8,657,985	8,155,011
Loans receivable	8,893,004	8,438,884	8,893,004	8,438,884	8,620,601
Total Commercial [Member] \| Total Commercial And Industrial [Member] \| Commercial Real Estate - Owner Occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Beginning balance			13,757	12,962
Allowance for loan losses: Ending balance	14,449	13,117	14,449	13,117
Allowance for loan losses: Individually evaluated for impairment	57	225	57	225
Allowance for loan losses: Amounts related to purchased credit impaired loans	172	403	172	403
Allowance for loan losses: Collectively evaluated for impairment	14,220	12,489	14,220	12,489
Loans: Individually evaluated for impairment	11,109	22,437	11,109	22,437
Loans: Purchased credit impaired loans	45,124	7,113	45,124	7,113
Loans: Collectively evaluated for impairment	2,678,146	2,270,721	2,678,146	2,270,721
Loans receivable	2,734,379	2,300,271	2,734,379	2,300,271	2,457,748
Total Commercial [Member] \| Total Commercial And Industrial [Member] \| Non-Purchased Credit Impaired Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs			(33,519)	(22,731)
Allowance for loan losses: Recoveries			5,946	13,516
Allowance for loan losses: Net provision for loan losses			29,812	2,130
Total Commercial [Member] \| Total Commercial And Industrial [Member] \| Non-Purchased Credit Impaired Loans [Member] \| Commercial Non-Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs			(33,382)	(15,401)
Allowance for loan losses: Recoveries			5,662	13,234
Allowance for loan losses: Net provision for loan losses			29,267	(5,073)
Total Commercial [Member] \| Total Commercial And Industrial [Member] \| Non-Purchased Credit Impaired Loans [Member] \| Commercial Real Estate - Owner Occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs			(137)	(7,330)
Allowance for loan losses: Recoveries			284	282
Allowance for loan losses: Net provision for loan losses			545	7,203
Residential Mortgages [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Beginning balance			23,782	24,844
Allowance for loan losses: Ending balance	21,479	24,310	21,479	24,310
Allowance for loan losses: Individually evaluated for impairment	183	163	183	163
Allowance for loan losses: Amounts related to purchased credit impaired loans	8,032	10,109	8,032	10,109
Allowance for loan losses: Collectively evaluated for impairment	13,264	14,038	13,264	14,038
Loans: Individually evaluated for impairment	4,301	3,061	4,301	3,061
Loans: Purchased credit impaired loans	93,450	107,535	93,450	107,535
Loans: Collectively evaluated for impairment	2,907,207	2,736,320	2,907,207	2,736,320
Loans receivable	3,004,958	2,846,916	3,004,958	2,846,916	2,910,081
Residential Mortgages [Member] \| Non-Purchased Credit Impaired Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs			(660)	(585)
Allowance for loan losses: Recoveries			433	1,854
Allowance for loan losses: Net provision for loan losses			(2,076)	(1,803)
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Beginning balance			25,938	30,503
Reduction as a result of sale of subsidiary				(6,648)
Allowance for loan losses: Ending balance	24,829	24,437	24,829	24,437
Allowance for loan losses: Individually evaluated for impairment	365	131	365	131
Allowance for loan losses: Amounts related to purchased credit impaired loans	300	433	300	433
Allowance for loan losses: Collectively evaluated for impairment	24,164	23,873	24,164	23,873
Loans: Individually evaluated for impairment	1,583	890	1,583	890
Loans: Purchased credit impaired loans	6,294	4,458	6,294	4,458
Loans: Collectively evaluated for impairment	2,144,448	2,117,180	2,144,448	2,117,180
Loans receivable	$ 2,152,325	$ 2,122,528	2,152,325	2,122,528	$ 2,147,867
Consumer [Member] \| Non-Purchased Credit Impaired Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs			(13,169)	(18,599)
Allowance for loan losses: Recoveries			2,866	4,028
Allowance for loan losses: Net provision for loan losses			$ 9,194	$ 15,153

Financing Receivable, Increase (Decrease) From Sale Of Subsidiary

No definition available.

Name:	hwc_FinancingReceivableIncreaseDecreaseFromSaleOfSubsidiary
Namespace Prefix:	hwc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Reserve for loans impairments recorded after acquisition as a result of current information and events which result in it being probable that estimated cash flows will be less than previously expected or because actual cash flows are less than cash flows previously expected. This relates to loans not accounted for as debt securities, with evidence of deterioration of credit quality since origination that was acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 30
-Section 15
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=118938799&loc=d3e13503-111538

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (b)(2)
-URI http://asc.fasb.org/extlink&oid=118939070&loc=d3e15032-111544

+ Details

Name:	us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAllowanceForLoanLosses
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The recorded balance, net of any applicable reductions (for example, unamortized accretable yield and allowance for loan losses). This relates to loans not accounted for debt securities with evidence of deterioration of credit quality since origination that were acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=118939070&loc=d3e15032-111544

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 30
-Section 15
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=118938799&loc=d3e13503-111538

+ Details

Name:	us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesCarryingAmountNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of allowance for credit loss on financing receivable. Excludes allowance for financing receivable covered under loss sharing agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953423-111524

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=118955202&loc=SL82895884-210446

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 13
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=119407570&loc=SL82919249-210447

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(7)(d))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 13
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=119407570&loc=SL82919249-210447

+ Details

Name:	us-gaap_FinancingReceivableAllowanceForCreditLosses
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

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

+ References

+ Details

Name:	us-gaap_FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

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

+ References

+ Details

Name:	us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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

- Definition

Amount of recovery of financing receivables doubtful of collection that were previously charged off.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 55
-Paragraph 79
-URI http://asc.fasb.org/extlink&oid=118955255&loc=SL82922352-210448

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(7)(d))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 13
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=119407570&loc=SL82919249-210447

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (c)(4)
-URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953423-111524

+ Details

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

- Definition

Amount of writeoff of financing receivable, charged against allowance for credit loss.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 13
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=119407570&loc=SL82919249-210447

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (c)(3)
-URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953423-111524

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 55
-Paragraph 79
-URI http://asc.fasb.org/extlink&oid=118955255&loc=SL82922352-210448

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(7)(d))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

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

- Definition

The balance of financing receivables that were collectively evaluated for impairment.

+ References

+ Details

Name:	us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The balance of financing receivables that were individually evaluated for impairment.

+ References

+ Details

Name:	us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=118952595&loc=d3e4428-111522

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5074-111524

+ Details

Name:	us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3602-108585

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.11)
-URI http://asc.fasb.org/extlink&oid=116637391&loc=SL114874048-224260

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953423-111524

+ Details

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

- Details

Name:	us-gaap_CreditLossStatusAxis=hwc_NonPurchasedCreditImpairedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=hwc_CommercialRealEstateIncomeProducingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_ConstructionLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_EquitySecuritiesByIndustryAxis=us-gaap_CommercialAndIndustrialSectorMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=hwc_CommercialNonRealEstateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=hwc_CommercialRealEstateOwnerOccupiedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ResidentialPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ConsumerPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: