Regulatory Matters (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Tier One Common Equity Based Capital [Abstract]
Common equity tier 1 capital (to risk-weighted assets), adequately-capitalized ratio	4.50%
Capital [Abstract]
Total Capital (to risk-weighted assets), adequately-capitalized ratio	8.00%
Tier One Risk Based Capital [Abstract]
Tier 1 capital (to risk-weighted assets), adequately capitalized ratio	6.00%
Tier One Leverage Capital [Abstract]
Tier 1 capital (to average assets), adequately-capitalized ratio	4.00%
Northrim Bancorp, Inc.
Tier One Common Equity Based Capital [Abstract]
Common equity tier 1 capital (to risk-weighted assets), actual amount	$ 171,190	$ 154,464
Common equity tier 1 capital (to risk-weighted assets), actual ratio	13.20%	12.01%
Common equity tier 1 capital (to risk-weighted assets), adequately-capitalized amount	$ 58,360	$ 57,876
Common equity tier 1 capital (to risk-weighted assets), adequately-capitalized ratio	4.50%	4.50%
Capital [Abstract]
Total Capital (to risk-weighted assets), actual amount	$ 204,927	$ 187,761
Total Capital (to risk-weighted assets), actual ratio	15.80%	14.60%
Total Capital (to risk-weighted assets), adequately-capitalized amount	$ 103,761	$ 102,883
Total Capital (to risk-weighted assets), adequately-capitalized ratio	8.00%	8.00%
Tier One Risk Based Capital [Abstract]
Tier 1 Capital (to risk-weighted assets), actual amount	$ 188,658	$ 171,653
Tier 1 Capital (to risk-weighted assets), actual ratio	14.54%	13.34%
Tier 1 Capital (to risk-weighted assets), adequately-capitalized amount	$ 77,851	$ 77,205
Tier 1 capital (to risk-weighted assets), adequately capitalized ratio	6.00%	6.00%
Tier One Leverage Capital [Abstract]
Tier I Capital (to average assets), actual amount	$ 188,658	$ 171,653
Tier I Capital (to average assets), actual ratio	12.59%	11.20%
Tier I Capital (to average assets), adequately-capitalized amount	$ 59,939	$ 61,305
Tier 1 capital (to average assets), adequately-capitalized ratio	4.00%	4.00%
Northrim Bank
Tier One Common Equity Based Capital [Abstract]
Common equity tier 1 capital (to risk-weighted assets), actual amount	$ 168,529	$ 156,317
Common equity tier 1 capital (to risk-weighted assets), actual ratio	13.07%	12.21%
Common equity tier 1 capital (to risk-weighted assets), adequately-capitalized amount	$ 58,025	$ 57,611
Common equity tier 1 capital (to risk-weighted assets), adequately-capitalized ratio	4.50%	4.50%
Common equity tier 1 capital (to risk-weighted assets), well-capitalized amount	$ 83,813	$ 83,215
Common equity tier 1 capital (to risk-weighted assets), well-capitalized ratio	6.50%	6.50%
Capital [Abstract]
Total Capital (to risk-weighted assets), actual amount	$ 184,695	$ 171,662
Total Capital (to risk-weighted assets), actual ratio	14.33%	13.41%
Total Capital (to risk-weighted assets), adequately-capitalized amount	$ 103,110	$ 102,408
Total Capital (to risk-weighted assets), adequately-capitalized ratio	8.00%	8.00%
Total Capital (to risk-weighted assets), well-capitalized amount	$ 128,887	$ 128,010
Total Capital (to risk-weighted assets), well-capitalized ratio	10.00%	10.00%
Tier One Risk Based Capital [Abstract]
Tier 1 Capital (to risk-weighted assets), actual amount	$ 168,529	$ 155,630
Tier 1 Capital (to risk-weighted assets), actual ratio	13.07%	12.16%
Tier 1 Capital (to risk-weighted assets), adequately-capitalized amount	$ 77,366	$ 76,791
Tier 1 capital (to risk-weighted assets), adequately capitalized ratio	6.00%	6.00%
Tier 1 Capital (to risk-weighted assets), well-capitalized amount	$ 103,155	$ 102,388
Tier 1 Capital (to risk-weighted assets), well-capitalized ratio	8.00%	8.00%
Tier One Leverage Capital [Abstract]
Tier I Capital (to average assets), actual amount	$ 168,529	$ 155,630
Tier I Capital (to average assets), actual ratio	11.30%	10.18%
Tier I Capital (to average assets), adequately-capitalized amount	$ 59,656	$ 61,151
Tier 1 capital (to average assets), adequately-capitalized ratio	4.00%	4.00%
Tier I Capital (to average assets), well-capitalized amount	$ 74,570	$ 76,439
Tier I Capital (to average assets), well-capitalized ratio	5.00%	5.00%

Tier One Common Equity Based Capital [Abstract]

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Tier One Common Equity Capital Required for Capital Adequacy

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Tier One Common Equity Capital Required for Capital Adequacy to Risk Based Assets

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Tier One Common Equity Capital Required to be Well Capitalized

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Tier One Common Equity Capital Required to be Well Capitalized to Risk Based Assets

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Tier One Common Equity Capital to Risk Based Assets

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The amount of total capital as defined in the regulations.

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-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
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The minimum amount of Total Capital required for capital adequacy purposes under the regulatory framework for prompt corrective action.

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The minimum Total risk based capital ratio (total capital divided by risk weighted assets) required for capital adequacy purposes under the regulatory framework for prompt corrective action.

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The amount of Total Capital required to be categorized as well as capitalized under the regulatory framework for prompt corrective action.

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The Total risk based capital ratio (total capital divided by risk weighted assets) required to be categorized as "well capitalized", in the regulatory framework for prompt corrective action.

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Total Capital divided by risk weighted assets as defined in the regulations.

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Tier 1 Leverage Capital as defined in the regulations. Also called Core Capital.

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The minimum amount of Tier 1 Leverage Capital required for capital adequacy purposes under the regulatory framework for prompt corrective action.

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The minimum amount of Tier 1 Leverage Capital for capital adequacy purposes divided by average assets as defined in the regulations.

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The amount of Tier 1 Leverage Capital required to be categorized as well capitalized under the regulatory framework for prompt corrective action.

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The amount of Tier 1 Leverage Capital required to be categorized as well capitalized divided by average assets as defined in the regulatory framework for prompt corrective action.

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Tier 1 Leverage Capital divided by average assets as defined in the regulations.

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Tier 1 Risk Based Capital as defined in the regulations.

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The minimum amount of Tier 1 Risk Based Capital required for capital adequacy purposes under the regulatory framework for prompt corrective action.

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The minimum Tier One Capital Ratio (Tier one capital divided by risk-weighted assets) required for capital adequacy purposes under the regulatory framework for prompt corrective action.

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-Publisher FASB
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The amount of Tier 1 Risk Based Capital required to be categorized as well capitalized under the regulatory framework for prompt corrective action.

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The Tier 1 capital ratio (Tier 1 capital divided by risk weighted assets) required to be categorized as "well capitalized" under the regulatory framework for prompt corrective action.

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Tier 1 capital divided by risk weighted assets as defined by regulations.

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