Stockholders' Equity - Actual Capital Amounts and Ratios (Details) $ in Thousands	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Parent Company
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Capital conservation buffer, ratio	2.50%
Actual, Amount
Total capital	$ 1,145,331	$ 1,104,863
Tier one capital	1,085,665	1,041,650
Common equity tier one capital	1,078,448	1,034,433
Tier one leverage capital	$ 1,085,665	$ 1,041,650
Ratio, Actual
Capital to risk weighted assets	0.1539	0.1713
Tier one risk based capital to risk weighted assets	0.1459	0.1615
Common equity tier one capital	0.1449	0.1604
Tier one leverage capital to average assets	0.1068	0.1123
Minimum Capital Adequacy Requirements, Amount
Capital required for capital adequacy	$ 595,313	$ 515,924
Tier one risk based capital required for capital adequacy	446,484	386,943
Common equity tier one capital required for capital adequacy	334,863	290,207
Tier one leverage capital required for capital adequacy	$ 406,643	$ 370,909
Minimum Capital Adequacy Requirements, Ratio
Capital required for capital adequacy to risk weighted assets	0.080	0.0800
Tier one risk based capital required for capital adequacy to risk weighted assets	0.060	0.0600
Common equity tier one capital required for capital adequacy to risk weighted assets	0.0450	0.0450
Tier one leverage capital required for capital adequacy to average assets	0.040	0.0400
Minimum Capital Adequacy Requirements With Capital Conservation Buffer, Amount
Capital required for capital adequacy with capital buffer	$ 781,348	$ 677,151
Tier one risk based capital required for capital adequacy with capital buffer	632,520	548,170
Common equity tier one risk based capital required for capital adequacy with capital buffer	520,899	451,434
Tier one leverage capital required for capital adequacy with capital buffer to average assets	$ 406,643	$ 370,909
Minimum Capital Adequacy Requirements With Capital Conservation Buffer, Ratio
Capital required for capital adequacy with capital buffer to risk weighted assets	0.1050	0.1050
Tier one risk based capital required for capital adequacy with capital buffer to risk weighted assets	0.0850	0.0850
Common equity tier one risk based capital requirement for capital adequacy with capital buffer to risk weighted assets	0.0700	0.0700
Tier one leverage capital requirement for capital adequacy with capital buffer to average assets	4.00%	4.00%
Columbia Bank
Actual, Amount
Total capital	$ 1,019,850	$ 962,137
Tier one capital	961,613	898,935
Common equity tier one capital	961,613	898,935
Tier one leverage capital	$ 961,613	$ 898,935
Ratio, Actual
Capital to risk weighted assets	0.1412	0.1539
Tier one risk based capital to risk weighted assets	0.1332	0.1438
Common equity tier one capital	0.1332	0.1438
Tier one leverage capital to average assets	0.0974	0.0980
Minimum Capital Adequacy Requirements, Amount
Capital required for capital adequacy	$ 577,656	$ 500,127
Tier one risk based capital required for capital adequacy	433,242	375,095
Common equity tier one capital required for capital adequacy	324,931	281,322
Tier one leverage capital required for capital adequacy	$ 394,968	$ 366,961
Minimum Capital Adequacy Requirements, Ratio
Capital required for capital adequacy to risk weighted assets	0.0800	0.0800
Tier one risk based capital required for capital adequacy to risk weighted assets	0.0600	0.0600
Common equity tier one capital required for capital adequacy to risk weighted assets	0.0450	0.0450
Tier one leverage capital required for capital adequacy to average assets	0.0400	0.0400
Minimum Capital Adequacy Requirements With Capital Conservation Buffer, Amount
Capital required for capital adequacy with capital buffer	$ 758,173	$ 656,417
Tier one risk based capital required for capital adequacy with capital buffer	613,759	531,385
Common equity tier one risk based capital required for capital adequacy with capital buffer	505,449	437,611
Tier one leverage capital required for capital adequacy with capital buffer to average assets	$ 394,968	$ 366,961
Minimum Capital Adequacy Requirements With Capital Conservation Buffer, Ratio
Capital required for capital adequacy with capital buffer to risk weighted assets	0.1050	0.1050
Tier one risk based capital required for capital adequacy with capital buffer to risk weighted assets	0.0850	0.0850
Common equity tier one risk based capital requirement for capital adequacy with capital buffer to risk weighted assets	0.0700	0.0700
Tier one leverage capital requirement for capital adequacy with capital buffer to average assets	4.00%	4.00%
To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount
Capital required to be well capitalized, amount	$ 722,070	$ 625,159
Tier one risk based capital required to be well capitalized, amount	577,656	500,127
Common equity tier one capital required to be well-capitalized, amount	469,345	406,353
Tier one leverage capital required to be well capitalized, amount	$ 493,711	$ 458,701
To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio
Capital required to be well capitalized to risk weighted assets, ratio	0.1000	0.1000
Tier one risk based capital required to be well capitalized to risk weighted assets, ratio	0.0800	0.0800
Common equity tier one capital required to be well-capitalized to risk weighted assets, ratio	0.0650	0.0650
Tier one leverage capital required to be well capitalized to average assets, ratio	0.0500	0.0500
Freehold Bank
Actual, Amount
Total capital	$ 44,725	$ 41,549
Tier one capital	43,298	41,537
Common equity tier one capital	43,298	41,537
Tier one leverage capital	$ 43,298	$ 41,537
Ratio, Actual
Capital to risk weighted assets	0.2292	0.2287
Tier one risk based capital to risk weighted assets	0.2219	0.2286
Common equity tier one capital	0.2219	0.2286
Tier one leverage capital to average assets	0.1519	0.1371
Minimum Capital Adequacy Requirements, Amount
Capital required for capital adequacy	$ 15,609	$ 14,534
Tier one risk based capital required for capital adequacy	11,706	10,901
Common equity tier one capital required for capital adequacy	8,780	8,176
Tier one leverage capital required for capital adequacy	$ 11,399	$ 12,118
Minimum Capital Adequacy Requirements, Ratio
Capital required for capital adequacy to risk weighted assets	0.0800	0.0800
Tier one risk based capital required for capital adequacy to risk weighted assets	0.0600	0.0600
Common equity tier one capital required for capital adequacy to risk weighted assets	0.0450	0.0450
Tier one leverage capital required for capital adequacy to average assets	0.0400	0.0400
Minimum Capital Adequacy Requirements With Capital Conservation Buffer, Amount
Capital required for capital adequacy with capital buffer	$ 20,486	$ 19,076
Tier one risk based capital required for capital adequacy with capital buffer	16,584	15,443
Common equity tier one risk based capital required for capital adequacy with capital buffer	13,657	12,717
Tier one leverage capital required for capital adequacy with capital buffer to average assets	$ 11,399	$ 12,118
Minimum Capital Adequacy Requirements With Capital Conservation Buffer, Ratio
Capital required for capital adequacy with capital buffer to risk weighted assets	0.1050	0.1050
Tier one risk based capital required for capital adequacy with capital buffer to risk weighted assets	0.0850	0.0850
Common equity tier one risk based capital requirement for capital adequacy with capital buffer to risk weighted assets	0.0700	0.0700
Tier one leverage capital requirement for capital adequacy with capital buffer to average assets	4.00%	4.00%
To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount
Capital required to be well capitalized, amount	$ 19,511	$ 18,168
Tier one risk based capital required to be well capitalized, amount	15,609	14,534
Common equity tier one capital required to be well-capitalized, amount	12,682	11,809
Tier one leverage capital required to be well capitalized, amount	$ 14,249	$ 15,147
To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio
Capital required to be well capitalized to risk weighted assets, ratio	0.1000	0.1000
Tier one risk based capital required to be well capitalized to risk weighted assets, ratio	0.0800	0.0800
Common equity tier one capital required to be well-capitalized to risk weighted assets, ratio	0.0650	0.0650
Tier one leverage capital required to be well capitalized to average assets, ratio	0.0500	0.0500