XML 130 R114.htm IDEA: XBRL DOCUMENT v3.25.4

Regulatory Matters - Schedule of Actual Capital Amounts and Ratios (Details) $ in Thousands	Dec. 31, 2025 USD ($)	Dec. 31, 2024 USD ($)
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Total Capital to Risk Weighted Assets, Ratio	0.124	0.123
Total Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Ratio	0.100
Tier 1 Capital to Risk Weighted Assets, Ratio	0.110	0.107
Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Ratio	0.080
Common Equity Tier 1 capital to risk weighted assets	0.103	0.099
Common Equity Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Ratio	0.065
Tier 1 Leverage Ratio	0.096	0.094
Tier 1 Leverage Ratio, To Be Well Capitalized by Regulatory Definition, Ratio	0.050
Lake Forest Bank
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Total Capital (to Risk Weighted Assets):	$ 913,408	$ 857,438
Total Capital to Risk Weighted Assets, Ratio	0.117	0.118
Total Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Amount	$ 780,590	$ 728,358
Total Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Ratio	0.100	0.100
Tier 1 Capital (to Risk Weighted Assets):	$ 858,940	$ 807,848
Tier 1 Capital to Risk Weighted Assets, Ratio	0.110	0.111
Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Amount	$ 624,472	$ 582,687
Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Ratio	0.080	0.080
Common Equity Tier 1 Capital to Risk Weighted Assets, Amount	$ 858,940	$ 807,848
Common Equity Tier 1 capital to risk weighted assets	0.110	0.111
Common Equity Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Amount	$ 507,384	$ 473,433
Common Equity Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Ratio	0.065	0.065
Tier 1 Leverage Ratio, Amount	$ 858,940	$ 807,848
Tier 1 Leverage Ratio	0.091	0.097
Tier 1 Leverage Ratio, To Be Well Capitalized by Regulatory Definition, Amount	$ 472,426	$ 416,233
Tier 1 Leverage Ratio, To Be Well Capitalized by Regulatory Definition, Ratio	0.050	0.050
Hinsdale Bank
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Total Capital (to Risk Weighted Assets):	$ 611,707	$ 543,925
Total Capital to Risk Weighted Assets, Ratio	0.117	0.119
Total Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Amount	$ 523,012	$ 458,046
Total Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Ratio	0.100	0.100
Tier 1 Capital (to Risk Weighted Assets):	$ 576,775	$ 512,323
Tier 1 Capital to Risk Weighted Assets, Ratio	0.110	0.112
Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Amount	$ 418,409	$ 366,437
Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Ratio	0.080	0.080
Common Equity Tier 1 Capital to Risk Weighted Assets, Amount	$ 576,775	$ 512,323
Common Equity Tier 1 capital to risk weighted assets	0.110	0.112
Common Equity Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Amount	$ 339,958	$ 297,730
Common Equity Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Ratio	0.065	0.065
Tier 1 Leverage Ratio, Amount	$ 576,775	$ 512,323
Tier 1 Leverage Ratio	0.099	0.096
Tier 1 Leverage Ratio, To Be Well Capitalized by Regulatory Definition, Amount	$ 291,840	$ 266,427
Tier 1 Leverage Ratio, To Be Well Capitalized by Regulatory Definition, Ratio	0.050	0.050
Wintrust Bank
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Total Capital (to Risk Weighted Assets):	$ 1,102,033	$ 1,164,532
Total Capital to Risk Weighted Assets, Ratio	0.125	0.127
Total Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Amount	$ 879,447	$ 915,950
Total Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Ratio	0.100	0.100
Tier 1 Capital (to Risk Weighted Assets):	$ 1,012,547	$ 1,069,171
Tier 1 Capital to Risk Weighted Assets, Ratio	0.115	0.117
Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Amount	$ 703,557	$ 732,760
Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Ratio	0.080	0.080
Common Equity Tier 1 Capital to Risk Weighted Assets, Amount	$ 1,012,547	$ 1,069,171
Common Equity Tier 1 capital to risk weighted assets	0.115	0.117
Common Equity Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Amount	$ 571,640	$ 595,367
Common Equity Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Ratio	0.065	0.065
Tier 1 Leverage Ratio, Amount	$ 1,012,547	$ 1,069,171
Tier 1 Leverage Ratio	0.105	0.111
Tier 1 Leverage Ratio, To Be Well Capitalized by Regulatory Definition, Amount	$ 481,193	$ 479,667
Tier 1 Leverage Ratio, To Be Well Capitalized by Regulatory Definition, Ratio	0.050	0.050
Libertyville Bank
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Total Capital (to Risk Weighted Assets):	$ 312,923	$ 276,568
Total Capital to Risk Weighted Assets, Ratio	0.120	0.118
Total Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Amount	$ 260,677	$ 234,181
Total Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Ratio	0.100	0.100
Tier 1 Capital (to Risk Weighted Assets):	$ 292,839	$ 258,709
Tier 1 Capital to Risk Weighted Assets, Ratio	0.112	0.111
Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Amount	$ 208,541	$ 187,345
Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Ratio	0.080	0.080
Common Equity Tier 1 Capital to Risk Weighted Assets, Amount	$ 292,839	$ 258,709
Common Equity Tier 1 capital to risk weighted assets	0.112	0.111
Common Equity Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Amount	$ 169,440	$ 152,218
Common Equity Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Ratio	0.065	0.065
Tier 1 Leverage Ratio, Amount	$ 292,839	$ 258,709
Tier 1 Leverage Ratio	0.094	0.095
Tier 1 Leverage Ratio, To Be Well Capitalized by Regulatory Definition, Amount	$ 156,035	$ 136,451
Tier 1 Leverage Ratio, To Be Well Capitalized by Regulatory Definition, Ratio	0.050	0.050
Barrington Bank
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Total Capital (to Risk Weighted Assets):	$ 519,425	$ 472,428
Total Capital to Risk Weighted Assets, Ratio	0.115	0.114
Total Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Amount	$ 449,975	$ 413,497
Total Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Ratio	0.100	0.100
Tier 1 Capital (to Risk Weighted Assets):	$ 491,794	$ 453,022
Tier 1 Capital to Risk Weighted Assets, Ratio	0.109	0.110
Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Amount	$ 359,980	$ 330,798
Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Ratio	0.080	0.080
Common Equity Tier 1 Capital to Risk Weighted Assets, Amount	$ 491,794	$ 453,022
Common Equity Tier 1 capital to risk weighted assets	0.109	0.110
Common Equity Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Amount	$ 292,484	$ 268,773
Common Equity Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Ratio	0.065	0.065
Tier 1 Leverage Ratio, Amount	$ 491,794	$ 453,022
Tier 1 Leverage Ratio	0.104	0.107
Tier 1 Leverage Ratio, To Be Well Capitalized by Regulatory Definition, Amount	$ 235,898	$ 212,429
Tier 1 Leverage Ratio, To Be Well Capitalized by Regulatory Definition, Ratio	0.050	0.050
Crystal Lake Bank
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Total Capital (to Risk Weighted Assets):	$ 218,761	$ 187,820
Total Capital to Risk Weighted Assets, Ratio	0.123	0.118
Total Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Amount	$ 177,720	$ 159,314
Total Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Ratio	0.100	0.100
Tier 1 Capital (to Risk Weighted Assets):	$ 204,432	$ 176,144
Tier 1 Capital to Risk Weighted Assets, Ratio	0.115	0.111
Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Amount	$ 142,176	$ 127,451
Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Ratio	0.080	0.080
Common Equity Tier 1 Capital to Risk Weighted Assets, Amount	$ 204,432	$ 176,144
Common Equity Tier 1 capital to risk weighted assets	0.115	0.111
Common Equity Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Amount	$ 115,518	$ 103,554
Common Equity Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Ratio	0.065	0.065
Tier 1 Leverage Ratio, Amount	$ 204,432	$ 176,144
Tier 1 Leverage Ratio	0.102	0.098
Tier 1 Leverage Ratio, To Be Well Capitalized by Regulatory Definition, Amount	$ 100,266	$ 89,519
Tier 1 Leverage Ratio, To Be Well Capitalized by Regulatory Definition, Ratio	0.050	0.050
Northbrook Bank
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Total Capital (to Risk Weighted Assets):	$ 554,744	$ 502,434
Total Capital to Risk Weighted Assets, Ratio	0.118	0.113
Total Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Amount	$ 469,918	$ 446,536
Total Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Ratio	0.100	0.100
Tier 1 Capital (to Risk Weighted Assets):	$ 524,287	$ 473,065
Tier 1 Capital to Risk Weighted Assets, Ratio	0.112	0.106
Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Amount	$ 375,934	$ 357,229
Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Ratio	0.080	0.080
Common Equity Tier 1 Capital to Risk Weighted Assets, Amount	$ 524,287	$ 473,065
Common Equity Tier 1 capital to risk weighted assets	0.112	0.106
Common Equity Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Amount	$ 305,447	$ 290,248
Common Equity Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Ratio	0.065	0.065
Tier 1 Leverage Ratio, Amount	$ 524,287	$ 473,065
Tier 1 Leverage Ratio	0.097	0.092
Tier 1 Leverage Ratio, To Be Well Capitalized by Regulatory Definition, Amount	$ 271,425	$ 256,737
Tier 1 Leverage Ratio, To Be Well Capitalized by Regulatory Definition, Ratio	0.050	0.050
Macatawa
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Total Capital (to Risk Weighted Assets):	$ 382,248	$ 307,829
Total Capital to Risk Weighted Assets, Ratio	0.127	0.163
Total Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Amount	$ 301,217	$ 189,233
Total Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Ratio	0.100	0.100
Tier 1 Capital (to Risk Weighted Assets):	$ 355,462	$ 293,541
Tier 1 Capital to Risk Weighted Assets, Ratio	0.118	0.155
Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Amount	$ 240,974	$ 151,387
Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Ratio	0.080	0.080
Common Equity Tier 1 Capital to Risk Weighted Assets, Amount	$ 355,462	$ 293,541
Common Equity Tier 1 capital to risk weighted assets	0.118	0.155
Common Equity Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Amount	$ 195,791	$ 123,002
Common Equity Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Ratio	0.065	0.065
Tier 1 Leverage Ratio, Amount	$ 355,462	$ 293,541
Tier 1 Leverage Ratio	0.108	0.101
Tier 1 Leverage Ratio, To Be Well Capitalized by Regulatory Definition, Amount	$ 164,001	$ 144,975
Tier 1 Leverage Ratio, To Be Well Capitalized by Regulatory Definition, Ratio	0.050	0.050
Schaumburg Bank
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Total Capital (to Risk Weighted Assets):	$ 246,955	$ 229,770
Total Capital to Risk Weighted Assets, Ratio	0.129	0.122
Total Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Amount	$ 191,443	$ 187,982
Total Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Ratio	0.100	0.100
Tier 1 Capital (to Risk Weighted Assets):	$ 234,406	$ 216,675
Tier 1 Capital to Risk Weighted Assets, Ratio	0.122	0.115
Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Amount	$ 153,154	$ 150,386
Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Ratio	0.080	0.080
Common Equity Tier 1 Capital to Risk Weighted Assets, Amount	$ 234,406	$ 216,675
Common Equity Tier 1 capital to risk weighted assets	0.122	0.115
Common Equity Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Amount	$ 124,438	$ 122,188
Common Equity Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Ratio	0.065	0.065
Tier 1 Leverage Ratio, Amount	$ 234,406	$ 216,675
Tier 1 Leverage Ratio	0.101	0.100
Tier 1 Leverage Ratio, To Be Well Capitalized by Regulatory Definition, Amount	$ 115,689	$ 108,031
Tier 1 Leverage Ratio, To Be Well Capitalized by Regulatory Definition, Ratio	0.050	0.050
Village Bank
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Total Capital (to Risk Weighted Assets):	$ 347,992	$ 310,037
Total Capital to Risk Weighted Assets, Ratio	0.116	0.115
Total Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Amount	$ 300,127	$ 270,656
Total Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Ratio	0.100	0.100
Tier 1 Capital (to Risk Weighted Assets):	$ 318,322	$ 286,808
Tier 1 Capital to Risk Weighted Assets, Ratio	0.106	0.106
Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Amount	$ 240,102	$ 216,524
Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Ratio	0.080	0.080
Common Equity Tier 1 Capital to Risk Weighted Assets, Amount	$ 318,322	$ 286,808
Common Equity Tier 1 capital to risk weighted assets	0.106	0.106
Common Equity Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Amount	$ 195,083	$ 175,926
Common Equity Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Ratio	0.065	0.065
Tier 1 Leverage Ratio, Amount	$ 318,322	$ 286,808
Tier 1 Leverage Ratio	0.094	0.096
Tier 1 Leverage Ratio, To Be Well Capitalized by Regulatory Definition, Amount	$ 168,839	$ 149,062
Tier 1 Leverage Ratio, To Be Well Capitalized by Regulatory Definition, Ratio	0.050	0.050
Beverly Bank
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Total Capital (to Risk Weighted Assets):	$ 266,507	$ 265,590
Total Capital to Risk Weighted Assets, Ratio	0.126	0.125
Total Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Amount	$ 211,477	$ 213,222
Total Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Ratio	0.100	0.100
Tier 1 Capital (to Risk Weighted Assets):	$ 250,149	$ 246,565
Tier 1 Capital to Risk Weighted Assets, Ratio	0.118	0.116
Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Amount	$ 169,182	$ 170,578
Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Ratio	0.080	0.080
Common Equity Tier 1 Capital to Risk Weighted Assets, Amount	$ 250,149	$ 246,565
Common Equity Tier 1 capital to risk weighted assets	0.118	0.116
Common Equity Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Amount	$ 137,460	$ 138,594
Common Equity Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Ratio	0.065	0.065
Tier 1 Leverage Ratio, Amount	$ 250,149	$ 246,565
Tier 1 Leverage Ratio	0.101	0.101
Tier 1 Leverage Ratio, To Be Well Capitalized by Regulatory Definition, Amount	$ 123,495	$ 122,295
Tier 1 Leverage Ratio, To Be Well Capitalized by Regulatory Definition, Ratio	0.050	0.050
Town Bank
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Total Capital (to Risk Weighted Assets):	$ 448,206	$ 387,911
Total Capital to Risk Weighted Assets, Ratio	0.121	0.114
Total Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Amount	$ 371,326	$ 340,161
Total Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Ratio	0.100	0.100
Tier 1 Capital (to Risk Weighted Assets):	$ 422,451	$ 366,265
Tier 1 Capital to Risk Weighted Assets, Ratio	0.114	0.108
Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Amount	$ 297,061	$ 272,129
Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Ratio	0.080	0.080
Common Equity Tier 1 Capital to Risk Weighted Assets, Amount	$ 422,451	$ 366,265
Common Equity Tier 1 capital to risk weighted assets	0.114	0.108
Common Equity Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Amount	$ 241,362	$ 221,105
Common Equity Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Ratio	0.065	0.065
Tier 1 Leverage Ratio, Amount	$ 422,451	$ 366,265
Tier 1 Leverage Ratio	0.095	0.089
Tier 1 Leverage Ratio, To Be Well Capitalized by Regulatory Definition, Amount	$ 221,588	$ 205,847
Tier 1 Leverage Ratio, To Be Well Capitalized by Regulatory Definition, Ratio	0.050	0.050
Wheaton Bank
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Total Capital (to Risk Weighted Assets):	$ 406,928	$ 347,365
Total Capital to Risk Weighted Assets, Ratio	0.113	0.114
Total Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Amount	$ 358,758	$ 304,003
Total Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Ratio	0.100	0.100
Tier 1 Capital (to Risk Weighted Assets):	$ 382,347	$ 323,221
Tier 1 Capital to Risk Weighted Assets, Ratio	0.107	0.106
Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Amount	$ 287,007	$ 243,202
Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Ratio	0.080	0.080
Common Equity Tier 1 Capital to Risk Weighted Assets, Amount	$ 382,347	$ 323,221
Common Equity Tier 1 capital to risk weighted assets	0.107	0.106
Common Equity Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Amount	$ 233,193	$ 197,602
Common Equity Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Ratio	0.065	0.065
Tier 1 Leverage Ratio, Amount	$ 382,347	$ 323,221
Tier 1 Leverage Ratio	0.090	0.091
Tier 1 Leverage Ratio, To Be Well Capitalized by Regulatory Definition, Amount	$ 212,275	$ 178,254
Tier 1 Leverage Ratio, To Be Well Capitalized by Regulatory Definition, Ratio	0.050	0.050
State Bank of the Lakes
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Total Capital (to Risk Weighted Assets):	$ 246,346	$ 213,869
Total Capital to Risk Weighted Assets, Ratio	0.120	0.116
Total Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Amount	$ 204,907	$ 184,932
Total Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Ratio	0.100	0.100
Tier 1 Capital (to Risk Weighted Assets):	$ 233,269	$ 203,972
Tier 1 Capital to Risk Weighted Assets, Ratio	0.114	0.110
Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Amount	$ 163,925	$ 147,946
Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Ratio	0.080	0.080
Common Equity Tier 1 Capital to Risk Weighted Assets, Amount	$ 233,269	$ 203,972
Common Equity Tier 1 capital to risk weighted assets	0.114	0.110
Common Equity Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Amount	$ 133,189	$ 120,206
Common Equity Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Ratio	0.065	0.065
Tier 1 Leverage Ratio, Amount	$ 233,269	$ 203,972
Tier 1 Leverage Ratio	0.099	0.098
Tier 1 Leverage Ratio, To Be Well Capitalized by Regulatory Definition, Amount	$ 118,454	$ 104,067
Tier 1 Leverage Ratio, To Be Well Capitalized by Regulatory Definition, Ratio	0.050	0.050
Old Plank Trail Bank
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Total Capital (to Risk Weighted Assets):	$ 311,608	$ 271,641
Total Capital to Risk Weighted Assets, Ratio	0.118	0.113
Total Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Amount	$ 265,015	$ 241,562
Total Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Ratio	0.100	0.100
Tier 1 Capital (to Risk Weighted Assets):	$ 292,554	$ 255,788
Tier 1 Capital to Risk Weighted Assets, Ratio	0.110	0.106
Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Amount	$ 212,012	$ 193,249
Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Ratio	0.080	0.080
Common Equity Tier 1 Capital to Risk Weighted Assets, Amount	$ 292,554	$ 255,788
Common Equity Tier 1 capital to risk weighted assets	0.110	0.106
Common Equity Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Amount	$ 172,260	$ 157,015
Common Equity Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Ratio	0.065	0.065
Tier 1 Leverage Ratio, Amount	$ 292,554	$ 255,788
Tier 1 Leverage Ratio	0.091	0.089
Tier 1 Leverage Ratio, To Be Well Capitalized by Regulatory Definition, Amount	$ 161,477	$ 143,480
Tier 1 Leverage Ratio, To Be Well Capitalized by Regulatory Definition, Ratio	0.050	0.050
St. Charles Bank
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Total Capital (to Risk Weighted Assets):	$ 334,965	$ 291,380
Total Capital to Risk Weighted Assets, Ratio	0.114	0.112
Total Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Amount	$ 292,758	$ 259,615
Total Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Ratio	0.100	0.100
Tier 1 Capital (to Risk Weighted Assets):	$ 315,028	$ 270,446
Tier 1 Capital to Risk Weighted Assets, Ratio	0.108	0.104
Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Amount	$ 234,206	$ 207,692
Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Ratio	0.080	0.080
Common Equity Tier 1 Capital to Risk Weighted Assets, Amount	$ 315,028	$ 270,446
Common Equity Tier 1 capital to risk weighted assets	0.108	0.104
Common Equity Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Amount	$ 190,293	$ 168,750
Common Equity Tier 1 Capital to Risk Weighted Assets, To Be Well Capitalized by Regulatory Definition, Ratio	0.065	0.065
Tier 1 Leverage Ratio, Amount	$ 315,028	$ 270,446
Tier 1 Leverage Ratio	0.095	0.093
Tier 1 Leverage Ratio, To Be Well Capitalized by Regulatory Definition, Amount	$ 166,595	$ 144,886
Tier 1 Leverage Ratio, To Be Well Capitalized by Regulatory Definition, Ratio	0.050	0.050

X

- Definition

Ratio of minimum Common Equity Tier 1 risk-based capital to risk-weighted assets categorized as well capitalized as defined by regulatory framework for prompt corrective action.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 505
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (c)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477270/942-505-50-1

+ Details

Name:	us-gaap_BankingRegulationCommonEquityTierOneRiskBasedCapitalRatioWellCapitalizedMinimum
Namespace Prefix:	us-gaap_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Amount of total capital as defined by regulatory framework.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 505
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (c)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477270/942-505-50-1

+ Details

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

X

- Definition

Amount of minimum total risk-based capital categorized as well capitalized as defined by regulatory framework for prompt corrective action.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 505
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (c)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477270/942-505-50-1

+ Details

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

X

- Definition

Ratio of minimum total risk-based capital to risk-weighted assets categorized as well capitalized as defined by regulatory framework for prompt corrective action.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 505
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (c)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477270/942-505-50-1

+ Details

Name:	us-gaap_CapitalRequiredToBeWellCapitalizedToRiskWeightedAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Ratio of total risk-based capital to risk-weighted assets as defined by regulatory framework.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 505
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (c)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477270/942-505-50-1

+ Details

Name:	us-gaap_CapitalToRiskWeightedAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Amount of Common Equity Tier 1 risk-based capital as defined by regulatory framework.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 505
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (c)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477270/942-505-50-1

+ Details

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

X

- Definition

Ratio of Common Equity Tier 1 risk-based capital to risk-weighted assets as defined by regulatory framework.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 505
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (c)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477270/942-505-50-1

+ Details

Name:	us-gaap_CommonEquityTierOneCapitalRatio
Namespace Prefix:	us-gaap_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Amount of minimum Common Equity Tier 1 risk-based capital categorized as well capitalized as defined by regulatory framework for prompt corrective action.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 505
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (c)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477270/942-505-50-1

+ Details

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

X

- 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

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 942
-SubTopic 505
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477270/942-505-50-1B

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 942
-SubTopic 505
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (c)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477270/942-505-50-1

+ Details

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

X

- Definition

Amount of Tier 1 leverage capital as defined by regulatory framework.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 505
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (c)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477270/942-505-50-1

+ Details

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

X

- Definition

Amount of minimum Tier 1 leverage capital categorized as well capitalized as defined by regulatory framework for prompt corrective action.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 505
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (c)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477270/942-505-50-1

+ Details

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

X

- Definition

Ratio of minimum Tier 1 leverage capital to average assets categorized as well capitalized as defined by regulatory framework for prompt corrective action.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 505
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (c)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477270/942-505-50-1

+ Details

Name:	us-gaap_TierOneLeverageCapitalRequiredToBeWellCapitalizedToAverageAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Ratio of Tier 1 capital to average assets as defined by regulatory framework.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 505
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (c)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477270/942-505-50-1

+ Details

Name:	us-gaap_TierOneLeverageCapitalToAverageAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Amount of Tier 1 risk-based capital as defined by regulatory framework.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 505
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (c)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477270/942-505-50-1

+ Details

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

X

- Definition

Amount of minimum Tier 1 risk-based capital categorized as well capitalized as defined by regulatory framework for prompt corrective action.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 505
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (c)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477270/942-505-50-1

+ Details

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

X

- Definition

Ratio of minimum Tier 1 risk-based capital to risk-weighted assets categorized as well capitalized as defined by regulatory framework for prompt corrective action.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 505
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (c)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477270/942-505-50-1

+ Details

Name:	us-gaap_TierOneRiskBasedCapitalRequiredToBeWellCapitalizedToRiskWeightedAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Ratio of Tier 1 risk-based capital to risk-weighted assets as defined by regulatory framework.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 505
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (c)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477270/942-505-50-1

+ Details

Name:	us-gaap_TierOneRiskBasedCapitalToRiskWeightedAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

X

- Details

Name:	dei_LegalEntityAxis=wtfc_LakeForestBankMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	dei_LegalEntityAxis=wtfc_HinsdaleBankMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	dei_LegalEntityAxis=wtfc_WintrustBankMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	dei_LegalEntityAxis=wtfc_LibertyvilleBankMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	dei_LegalEntityAxis=wtfc_BarringtonBankMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	dei_LegalEntityAxis=wtfc_CrystalLakeBankMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	dei_LegalEntityAxis=wtfc_NorthbrookBankMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	dei_LegalEntityAxis=wtfc_MacatawaBankCorporationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	dei_LegalEntityAxis=wtfc_SchaumburgBankMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	dei_LegalEntityAxis=wtfc_VillageBankMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	dei_LegalEntityAxis=wtfc_BeverlyBankMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	dei_LegalEntityAxis=wtfc_TownBankMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	dei_LegalEntityAxis=wtfc_WheatonBankMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	dei_LegalEntityAxis=wtfc_StateBankOfLakesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	dei_LegalEntityAxis=wtfc_OldPlankTrailBankMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	dei_LegalEntityAxis=wtfc_StCharlesBankMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: