| Document and Entity Information | Oct. 24, 2019 |
| Document And Entity Information [Line Items] | |
| Entity Registrant Name | PS BUSINESS PARKS INC/CA |
| Current Fiscal Year End Date | --12-31 |
| Amendment Flag | false |
| Entity Central Index Key | 0000866368 |
| Document Type | 8-K |
| Document Period End Date | Oct. 24, 2019 |
| Entity Incorporation, State or Country Code | CA |
| Entity File Number | 001-10709 |
| Entity Tax Identification Number | 95-4300881 |
| Entity Address, Address Line One | 701 Western Avenue |
| Entity Address, City or Town | Glendale |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 91201-2349 |
| City Area Code | 818 |
| Local Phone Number | 244-8080 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Common Stock [Member] | |
| Document And Entity Information [Line Items] | |
| Title of 12(b) Security | Common Stock, $0.01 par value per share |
| Trading Symbol | PSB |
| Security Exchange Name | NYSE |
| Series U Preferred Stock [Member] | |
| Document And Entity Information [Line Items] | |
| Title of 12(b) Security | Depositary Shares Each Representing 1/1,000 of a Share of 5.750% Cumulative Preferred Stock, Series U, $0.01 par value per share |
| Trading Symbol | PSBPrU |
| Security Exchange Name | NYSE |
| Series V Preferred Stock [Member] | |
| Document And Entity Information [Line Items] | |
| Title of 12(b) Security | Depositary Shares Each Representing 1/1,000 of a Share of 5.700% Cumulative Preferred Stock, Series V, $0.01 par value per share |
| Trading Symbol | PSBPrV |
| Security Exchange Name | NYSE |
| Series W Preferred Stock [Member] | |
| Document And Entity Information [Line Items] | |
| Title of 12(b) Security | Depositary Shares Each Representing 1/1,000 of a Share of 5.200% Cumulative Preferred Stock, Series W, $0.01 par value per share |
| Trading Symbol | PSBPrW |
| Security Exchange Name | NYSE |
| Series X Preferred Stock [Member] | |
| Document And Entity Information [Line Items] | |
| Title of 12(b) Security | Depositary Shares Each Representing 1/1,000 of a Share of 5.250% Cumulative Preferred Stock, Series X, $0.01 par value per share |
| Trading Symbol | PSBPrX |
| Security Exchange Name | NYSE |
| Series Y Preferred Stock [Member] | |
| Document And Entity Information [Line Items] | |
| Title of 12(b) Security | Depositary Shares Each Representing 1/1,000 of a Share of 5.200% Cumulative Preferred Stock, Series Y, $0.01 par value per share |
| Trading Symbol | PSBPrY |
| Security Exchange Name | NYSE |
