REGULATORY CAPITAL REQUIREMENTS AND RESTRICTIONS ON SUBSIDIARY DIVIDENDS (Details) $ in Thousands	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Total Capital (to Risk-Weighted Assets)
Actual - Amount	$ 2,237,035	$ 2,204,829
Actual - Ratio	0.1453	0.1476
For Capital Adequacy Purposes - Amount	$ 1,231,972	$ 1,194,970
For Capital Adequacy Purposes - Ratio	0.0800	0.0800
To Be Well Capitalized Under Prompt Corrective Action - Amount	$ 1,539,965
To Be Well Capitalized Under Prompt Corrective Action - Ratio	0.1000
Tier 1 Capital (to Risk-Weighted Assets)
Actual - Amount	$ 1,800,542	$ 1,763,990
Actual - Ratio	0.1169	0.1181
For Capital Adequacy Purposes - Amount	$ 923,979	$ 896,228
For Capital Adequacy Purposes - Ratio	0.0600	0.0600
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount	$ 923,979
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio	0.0600
Common Equity Tier 1 (to Risk-Weighted Assets)
Actual - Amount	$ 1,689,837	$ 1,653,285
Actual - Ratio	10.97%	11.07%
For Capital Adequacy Purposes - Amount	$ 692,984	$ 672,171
For Capital Adequacy Purposes - Ratio	4.50%	4.50%
Tier 1 Capital (to Average Assets)
Actual - Amount	$ 1,800,542	$ 1,763,990
Actual - Ratio	0.0944	0.0913
For Capital Adequacy Purposes - Amount	$ 763,309	$ 772,911
For Capital Adequacy Purposes - Ratio	0.0400	0.0400
Minimum Capital Requirement
Tier 1 Capital (to Average Assets)
Retained earnings available for dividend payments	$ 743,300
Capital Requirement to Remain Well Capitalized
Tier 1 Capital (to Average Assets)
Retained earnings available for dividend payments	436,900
HTLF Bank
Total Capital (to Risk-Weighted Assets)
Actual - Amount	$ 1,969,006	$ 824,069
Actual - Ratio	0.1285	0.1172
For Capital Adequacy Purposes - Amount	$ 1,225,669	$ 562,497
For Capital Adequacy Purposes - Ratio	0.0800	0.0800
To Be Well Capitalized Under Prompt Corrective Action - Amount	$ 1,532,087	$ 703,122
To Be Well Capitalized Under Prompt Corrective Action - Ratio	0.1000	0.1000
Tier 1 Capital (to Risk-Weighted Assets)
Actual - Amount	$ 1,829,972	$ 762,103
Actual - Ratio	0.1194	0.1084
For Capital Adequacy Purposes - Amount	$ 919,252	$ 421,873
For Capital Adequacy Purposes - Ratio	0.0600	0.0600
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount	$ 1,225,669	$ 562,497
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio	0.0800	0.0800
Common Equity Tier 1 (to Risk-Weighted Assets)
Actual - Amount	$ 1,829,972	$ 762,103
Actual - Ratio	11.94%	10.84%
For Capital Adequacy Purposes - Amount	$ 689,439	$ 316,405
For Capital Adequacy Purposes - Ratio	4.50%	4.50%
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount	$ 995,856	$ 457,029
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio	6.50%	6.50%
Tier 1 Capital (to Average Assets)
Actual - Amount	$ 1,829,972	$ 762,103
Actual - Ratio	0.0926	0.0864
For Capital Adequacy Purposes - Amount	$ 790,709	$ 352,914
For Capital Adequacy Purposes - Ratio	0.0400	0.0400
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount	$ 988,386	$ 441,143
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio	0.0500	0.0500
Dubuque Bank and Trust Company
Total Capital (to Risk-Weighted Assets)
Actual - Amount		$ 184,096
Actual - Ratio		0.1301
For Capital Adequacy Purposes - Amount		$ 113,197
For Capital Adequacy Purposes - Ratio		0.0800
To Be Well Capitalized Under Prompt Corrective Action - Amount		$ 141,497
To Be Well Capitalized Under Prompt Corrective Action - Ratio		0.1000
Tier 1 Capital (to Risk-Weighted Assets)
Actual - Amount		$ 174,684
Actual - Ratio		0.1235
For Capital Adequacy Purposes - Amount		$ 84,898
For Capital Adequacy Purposes - Ratio		0.0600
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount		$ 113,197
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio		0.0800
Common Equity Tier 1 (to Risk-Weighted Assets)
Actual - Amount		$ 174,684
Actual - Ratio		12.35%
For Capital Adequacy Purposes - Amount		$ 63,674
For Capital Adequacy Purposes - Ratio		4.50%
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount		$ 91,973
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio		6.50%
Tier 1 Capital (to Average Assets)
Actual - Amount		$ 174,684
Actual - Ratio		0.0808
For Capital Adequacy Purposes - Amount		$ 86,473
For Capital Adequacy Purposes - Ratio		0.0400
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount		$ 108,091
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio		0.0500
Wisconsin Bank & Trust
Total Capital (to Risk-Weighted Assets)
Actual - Amount		$ 128,490
Actual - Ratio		0.1312
For Capital Adequacy Purposes - Amount		$ 78,336
For Capital Adequacy Purposes - Ratio		0.0800
To Be Well Capitalized Under Prompt Corrective Action - Amount		$ 97,920
To Be Well Capitalized Under Prompt Corrective Action - Ratio		0.1000
Tier 1 Capital (to Risk-Weighted Assets)
Actual - Amount		$ 119,231
Actual - Ratio		0.1218
For Capital Adequacy Purposes - Amount		$ 58,752
For Capital Adequacy Purposes - Ratio		0.0600
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount		$ 78,336
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio		0.0800
Common Equity Tier 1 (to Risk-Weighted Assets)
Actual - Amount		$ 119,231
Actual - Ratio		12.18%
For Capital Adequacy Purposes - Amount		$ 44,064
For Capital Adequacy Purposes - Ratio		4.50%
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount		$ 63,648
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio		6.50%
Tier 1 Capital (to Average Assets)
Actual - Amount		$ 119,231
Actual - Ratio		0.0922
For Capital Adequacy Purposes - Amount		$ 51,753
For Capital Adequacy Purposes - Ratio		0.0400
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount		$ 64,691
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio		0.0500
New Mexico Bank & Trust
Total Capital (to Risk-Weighted Assets)
Actual - Amount		$ 238,190
Actual - Ratio		0.1323
For Capital Adequacy Purposes - Amount		$ 144,059
For Capital Adequacy Purposes - Ratio		0.0800
To Be Well Capitalized Under Prompt Corrective Action - Amount		$ 180,073
To Be Well Capitalized Under Prompt Corrective Action - Ratio		0.1000
Tier 1 Capital (to Risk-Weighted Assets)
Actual - Amount		$ 223,602
Actual - Ratio		0.1242
For Capital Adequacy Purposes - Amount		$ 108,044
For Capital Adequacy Purposes - Ratio		0.0600
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount		$ 144,059
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio		0.0800
Common Equity Tier 1 (to Risk-Weighted Assets)
Actual - Amount		$ 223,602
Actual - Ratio		12.42%
For Capital Adequacy Purposes - Amount		$ 81,033
For Capital Adequacy Purposes - Ratio		4.50%
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount		$ 117,048
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio		6.50%
Tier 1 Capital (to Average Assets)
Actual - Amount		$ 223,602
Actual - Ratio		0.0812
For Capital Adequacy Purposes - Amount		$ 110,214
For Capital Adequacy Purposes - Ratio		0.0400
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount		$ 137,767
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio		0.0500
Rocky Mountain Bank
Total Capital (to Risk-Weighted Assets)
Actual - Amount		$ 69,792
Actual - Ratio		0.1284
For Capital Adequacy Purposes - Amount		$ 43,489
For Capital Adequacy Purposes - Ratio		0.0800
To Be Well Capitalized Under Prompt Corrective Action - Amount		$ 54,361
To Be Well Capitalized Under Prompt Corrective Action - Ratio		0.1000
Tier 1 Capital (to Risk-Weighted Assets)
Actual - Amount		$ 63,814
Actual - Ratio		0.1174
For Capital Adequacy Purposes - Amount		$ 32,617
For Capital Adequacy Purposes - Ratio		0.0600
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount		$ 43,489
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio		0.0800
Common Equity Tier 1 (to Risk-Weighted Assets)
Actual - Amount		$ 63,814
Actual - Ratio		11.74%
For Capital Adequacy Purposes - Amount		$ 24,463
For Capital Adequacy Purposes - Ratio		4.50%
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount		$ 35,335
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio		6.50%
Tier 1 Capital (to Average Assets)
Actual - Amount		$ 63,814
Actual - Ratio		0.0849
For Capital Adequacy Purposes - Amount		$ 30,064
For Capital Adequacy Purposes - Ratio		0.0400
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount		$ 37,580
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio		0.0500
Bank of Blue Valley
Total Capital (to Risk-Weighted Assets)
Actual - Amount		$ 162,131
Actual - Ratio		0.1607
For Capital Adequacy Purposes - Amount		$ 80,689
For Capital Adequacy Purposes - Ratio		0.0800
To Be Well Capitalized Under Prompt Corrective Action - Amount		$ 100,861
To Be Well Capitalized Under Prompt Corrective Action - Ratio		0.1000
Tier 1 Capital (to Risk-Weighted Assets)
Actual - Amount		$ 155,002
Actual - Ratio		0.1537
For Capital Adequacy Purposes - Amount		$ 60,516
For Capital Adequacy Purposes - Ratio		0.0600
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount		$ 80,689
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio		0.0800
Common Equity Tier 1 (to Risk-Weighted Assets)
Actual - Amount		$ 155,002
Actual - Ratio		15.37%
For Capital Adequacy Purposes - Amount		$ 45,387
For Capital Adequacy Purposes - Ratio		4.50%
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount		$ 65,560
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio		6.50%
Tier 1 Capital (to Average Assets)
Actual - Amount		$ 155,002
Actual - Ratio		0.1075
For Capital Adequacy Purposes - Amount		$ 57,676
For Capital Adequacy Purposes - Ratio		0.0400
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount		$ 72,095
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio		0.0500
First Bank & Trust
Total Capital (to Risk-Weighted Assets)
Actual - Amount		$ 288,518
Actual - Ratio		0.1351
For Capital Adequacy Purposes - Amount		$ 170,835
For Capital Adequacy Purposes - Ratio		0.0800
To Be Well Capitalized Under Prompt Corrective Action - Amount		$ 213,543
To Be Well Capitalized Under Prompt Corrective Action - Ratio		0.1000
Tier 1 Capital (to Risk-Weighted Assets)
Actual - Amount		$ 267,169
Actual - Ratio		0.1251
For Capital Adequacy Purposes - Amount		$ 128,126
For Capital Adequacy Purposes - Ratio		0.0600
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount		$ 170,835
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio		0.0800
Common Equity Tier 1 (to Risk-Weighted Assets)
Actual - Amount		$ 267,169
Actual - Ratio		12.51%
For Capital Adequacy Purposes - Amount		$ 96,094
For Capital Adequacy Purposes - Ratio		4.50%
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount		$ 138,803
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio		6.50%
Tier 1 Capital (to Average Assets)
Actual - Amount		$ 267,169
Actual - Ratio		0.0929
For Capital Adequacy Purposes - Amount		$ 115,026
For Capital Adequacy Purposes - Ratio		0.0400
To Be Well Capitalized Under Prompt Corrective Action Provisions - Amount		$ 143,782
To Be Well Capitalized Under Prompt Corrective Action Provisions - Ratio		0.0500