Regulatory Matters - Summary of Company's and Equity Bank's Capital Amounts and Ratios (Detail) $ in Thousands	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total capital to risk weighted assets, To Be Well Capitalized Under Prompt Corrective Provisions, Actual Ratio		0.10
Tier 1 capital to risk weighted assets, To Be Well Capitalized Under Prompt Corrective Provisions, Actual Ratio		0.08
Common equity Tier 1 capital to risk weighted assets, To Be Well Capitalized Under Prompt Corrective Provisions, Actual Ratio		6.50%
Tier 1 leverage to average assets, To Be Well Capitalized Under Prompt Corrective Provisions, Actual Ratio		0.05
Equity Bancshares, Inc. [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total capital to risk weighted assets, Actual Amount	$ 603,593	$ 571,514
Total capital to risk weighted assets, Actual Ratio	0.1608	0.1596
Tier 1 capital to risk weighted assets, Actual Amount	$ 483,539	$ 453,718
Tier 1 capital to risk weighted assets, Actual Ratio	0.1288	0.1267
Common equity Tier 1 capital to risk weighted assets, Actual Amount	$ 460,285	$ 430,794
Common equity Tier 1 capital to risk weighted assets, Actual Ratio	0.1226	0.1203
Tier 1 leverage to average assets, Actual Amount	$ 483,539	$ 453,718
Tier 1 leverage to average assets, Actual Ratio	0.0961	0.0909
Equity Bank [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total capital to risk weighted assets, Actual Amount	$ 588,165	$ 546,503
Total capital to risk weighted assets, Actual Ratio	0.1571	0.1528
Total capital to risk weighted assets, To Be Well Capitalized Under Prompt Corrective Provisions, Actual Amount	$ 374,445	$ 357,758
Total capital to risk weighted assets, To Be Well Capitalized Under Prompt Corrective Provisions, Actual Ratio	0.1000	0.1000
Tier 1 capital to risk weighted assets, Actual Amount	$ 541,354	$ 501,711
Tier 1 capital to risk weighted assets, Actual Ratio	0.1446	0.1402
Tier 1 capital to risk weighted assets, To Be Well Capitalized Under Prompt Corrective Provisions, Actual Amount	$ 299,556	$ 286,206
Tier 1 capital to risk weighted assets, To Be Well Capitalized Under Prompt Corrective Provisions, Actual Ratio	0.0800	0.0800
Common equity Tier 1 capital to risk weighted assets, Actual Amount	$ 541,354	$ 501,711
Common equity Tier 1 capital to risk weighted assets, Actual Ratio	0.1446	0.1402
Common equity Tier 1 capital to risk weighted assets, To Be Well Capitalized Under Prompt Corrective Provisions, Actual Amount	$ 243,390	$ 232,543
Common equity Tier 1 capital to risk weighted assets, To Be Well Capitalized Under Prompt Corrective Provisions, Actual Ratio	6.50%	6.50%
Tier 1 leverage to average assets, Actual Amount	$ 541,354	$ 501,711
Tier 1 leverage to average assets, Actual Ratio	0.1077	0.1007
Tier 1 leverage to average assets, To Be Well Capitalized Under Prompt Corrective Provisions, Actual Amount	$ 251,332	$ 249,226
Tier 1 leverage to average assets, To Be Well Capitalized Under Prompt Corrective Provisions, Actual Ratio	0.0500	0.0500
Base III Phase-In [Member] | Equity Bancshares, Inc. [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total capital to risk weighted assets, Minimum Required for Capital Adequacy Purposes, Actual Amount	$ 394,072	$ 376,013
Total capital to risk weighted assets, Minimum Required for Capital Adequacy Purposes, Actual Ratio	0.1050	0.1050
Tier 1 capital to risk weighted assets, Minimum Required for Capital Adequacy Purposes, Actual Amount	$ 319,011	$ 304,391
Tier 1 capital to risk weighted assets, Minimum Required for Capital Adequacy Purposes, Actual Ratio	0.0850	0.0850
Common equity Tier 1 capital to risk weighted assets, Minimum Required for Capital Adequacy Purposes, Actual Amount	$ 262,715	$ 250,675
Common equity Tier 1 capital to risk weighted assets, Minimum Required for Capital Adequacy Purposes, Actual Ratio	7.00%	7.00%
Tier 1 leverage to average assets, Minimum Required for Capital Adequacy Purposes, Actual Amount	$ 201,288	$ 199,563
Tier 1 leverage to average assets, Minimum Required for Capital Adequacy Purposes, Actual Ratio	0.0400	0.0400
Base III Phase-In [Member] | Equity Bank [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total capital to risk weighted assets, Minimum Required for Capital Adequacy Purposes, Actual Amount	$ 393,168	$ 375,646
Total capital to risk weighted assets, Minimum Required for Capital Adequacy Purposes, Actual Ratio	0.1050	0.1050
Tier 1 capital to risk weighted assets, Minimum Required for Capital Adequacy Purposes, Actual Amount	$ 318,279	$ 304,094
Tier 1 capital to risk weighted assets, Minimum Required for Capital Adequacy Purposes, Actual Ratio	0.0850	0.0850
Common equity Tier 1 capital to risk weighted assets, Minimum Required for Capital Adequacy Purposes, Actual Amount	$ 262,112	$ 250,430
Common equity Tier 1 capital to risk weighted assets, Minimum Required for Capital Adequacy Purposes, Actual Ratio	7.00%	7.00%
Tier 1 leverage to average assets, Minimum Required for Capital Adequacy Purposes, Actual Amount	$ 201,066	$ 199,381
Tier 1 leverage to average assets, Minimum Required for Capital Adequacy Purposes, Actual Ratio	0.0400	0.0400