Regulatory Capital Requirements (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common Equity Tier One Capital Required for Capital Adequacy	$ 211,110	$ 197,189
Common Equity Tier One Capital Required for Capital Adequacy to Average Assets	4.50%	4.50%
Common Equity Tier One Capital	$ 541,154	$ 510,618
Common Equity Tier One Capital to Average Assets	11.50%	11.70%
Tier One Leverage Capital Required for Capital Adequacy	$ 212,578	$ 201,920
Tier One Leverage Capital Required for Capital Adequacy to Average Assets	4.00%	4.00%
Tier One Leverage Capital	$ 561,749	$ 530,920
Tier One Leverage Capital to Average Assets	10.60%	10.50%
Tier One Risk Based Capital Required for Capital Adequacy	$ 281,479	$ 262,918
Tier One Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets	6.00%	6.00%
Tier One Risk Based Capital	$ 561,749	$ 530,920
Tier One Risk Based Capital to Risk Weighted Assets	12.00%	12.10%
Capital Required for Capital Adequacy	$ 375,306	$ 350,558
Capital Required for Capital Adequacy to Risk Weighted Assets	8.00%	8.00%
Capital	$ 598,226	$ 566,268
Capital to Risk Weighted Assets	12.80%	12.90%
Capital Conservation Buffer, Company	4.80%
Capital Conservation Buffer, Bank	4.30%
Heritage Bank
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common Equity Tier One Capital Required for Capital Adequacy	$ 211,017	$ 197,004
Common Equity Tier One Capital Required for Capital Adequacy to Average Assets	4.50%	4.50%
Common Equity Tier One Capital Required to be Well-Capitalized	$ 304,803	$ 284,561
Common Equity Tier One Capital Required to be Well Capitalized to Average Assets	6.50%	6.50%
Common Equity Tier One Capital	$ 538,560	$ 513,993
Common Equity Tier One Capital to Average Assets	11.50%	11.70%
Tier One Leverage Capital Required for Capital Adequacy	$ 211,187	$ 203,339
Tier One Leverage Capital Required for Capital Adequacy to Average Assets	4.00%	4.00%
Tier One Leverage Capital Required to be Well Capitalized	$ 263,984	$ 254,174
Tier One Leverage Capital Required to be Well Capitalized to Average Assets	5.00%	5.00%
Tier One Leverage Capital	$ 538,560	$ 513,993
Tier One Leverage Capital to Average Assets	10.20%	10.10%
Tier One Risk Based Capital Required for Capital Adequacy	$ 281,356	$ 262,671
Tier One Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets	6.00%	6.00%
Tier One Risk Based Capital Required to be Well Capitalized	$ 375,142	$ 350,229
Tier One Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets	8.00%	8.00%
Tier One Risk Based Capital	$ 538,560	$ 513,993
Tier One Risk Based Capital to Risk Weighted Assets	11.50%	11.70%
Capital Required for Capital Adequacy	$ 375,142	$ 350,229
Capital Required for Capital Adequacy to Risk Weighted Assets	8.00%	8.00%
Capital Required to be Well Capitalized	$ 468,927	$ 437,786
Capital Required to be Well Capitalized to Risk Weighted Assets	10.00%	10.00%
Capital	$ 575,037	$ 549,341
Capital to Risk Weighted Assets	12.30%	12.50%

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Common Equity Tier One Capital Required for Capital Adequacy to Average Assets

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Common Equity Tier One Capital to Average Assets

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The amount of total capital as defined in the regulations.

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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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Amount of Common Equity Tier One Risk-based Capital, as defined by regulatory framework.

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Amount of Common Equity Tier 1 Risk-based Capital required to be categorized as adequately capitalized under regulatory framework for prompt corrective action.

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

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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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Tier 1 Risk Based Capital as defined in the regulations.

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