Regulatory Capital (Details) $ in Thousands	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)
Regulatory Capital
Capital conservation buffer	2.50%
Total capital (to risk-weighted assets)
Actual, Amount	$ 2,805,336	$ 2,724,988
Actual, Ratio	0.1449	0.1461
Minimum capital requirement, Amount	$ 1,548,647	$ 1,492,211
Minimum capital requirement, Ratio	0.0800	0.0800
Tier 1 capital (to risk-weighted assets)
Actual, Amount	$ 2,456,084	$ 2,397,716
Actual, Ratio	0.1269	0.1285
Minimum capital requirement, Amount	$ 1,161,486	$ 1,119,158
Minimum capital requirement, Ratio	0.0600	0.0600
Common Equity Tier 1 (to risk-weighted assets)
Actual, Amount	$ 2,456,084	$ 2,397,716
Actual, Ratio	0.1269	0.1285
Minimum capital requirement, Amount	$ 871,114	$ 839,369
Minimum capital requirement, Ratio	4.50%	4.50%
Tier 1 capital (to average assets)
Actual, Amount	$ 2,456,084	$ 2,397,716
Actual, Ratio	0.0893	0.0871
Minimum capital requirement, Amount	$ 1,099,921	$ 1,101,349
Minimum capital requirement, Ratio	0.0400	0.0400
Glacier Bank
Total capital (to risk-weighted assets)
Actual, Amount	$ 2,629,308	$ 2,621,674
Actual, Ratio	0.1359	0.1407
Minimum capital requirement, Amount	$ 1,547,240	$ 1,490,668
Minimum capital requirement, Ratio	0.0800	0.0800
Well capitalized requirement, Amount	$ 1,934,050	$ 1,863,335
Well capitalized requirement, Ratio	0.1000	0.1000
Tier 1 capital (to risk-weighted assets)
Actual, Amount	$ 2,410,556	$ 2,424,902
Actual, Ratio	0.1246	0.1301
Minimum capital requirement, Amount	$ 1,160,430	$ 1,118,001
Minimum capital requirement, Ratio	0.0600	0.0600
Well capitalized requirement, Amount	$ 1,547,240	$ 1,490,668
Well capitalized requirement, Ratio	0.0800	0.0800
Common Equity Tier 1 (to risk-weighted assets)
Actual, Amount	$ 2,410,556	$ 2,424,902
Actual, Ratio	0.1246	0.1300
Minimum capital requirement, Amount	$ 870,323	$ 838,501
Minimum capital requirement, Ratio	4.50%	4.50%
Well capitalized requirement, Amount	$ 1,257,133	$ 1,211,168
Well capitalized requirement, Ratio	6.50%	6.50%
Tier 1 capital (to average assets)
Actual, Amount	$ 2,410,556	$ 2,424,902
Actual, Ratio	0.0877	0.0881
Minimum capital requirement, Amount	$ 1,099,231	$ 1,100,600
Minimum capital requirement, Ratio	0.0400	0.0400
Well capitalized requirement, Amount	$ 1,374,039	$ 1,375,750
Well capitalized requirement, Ratio	0.0500	0.0500