Basis of Presentation and Summary of Significant Accounting Policies	6 Months Ended
Jun. 30, 2014
Basis of Presentation and Summary of Significant Accounting Policies [Abstract]
Basis of Presentation and Significant Accounting Policies [Text Block]	Basis of Presentation and Summary of Significant Accounting Policies Boston Private Financial Holdings, Inc. (the “Company” or “BPFH”), is a bank holding company (the “Holding Company”) with three reportable segments: Private Banking, Investment Management, and Wealth Advisory. Boston Private Bank & Trust Company (the “Bank” or “Boston Private Bank”) is a trust company chartered by The Commonwealth of Massachusetts, insured by the Federal Deposit Insurance Corporation (the “FDIC”), and a wholly-owned subsidiary of the Company. Boston Private Bank currently operates in three geographic markets: New England, San Francisco Bay, and Southern California. The Investment Management segment has two consolidated affiliates, consisting of Dalton, Greiner, Hartman, Maher & Co., LLC (“DGHM”) and Anchor Capital Advisors, LLC (“Anchor”), both of which are registered investment advisers (together, the “Investment Managers”). The Wealth Advisory segment has two consolidated affiliates, consisting of KLS Professional Advisors Group, LLC (“KLS”) and Bingham, Osborn & Scarborough, LLC (“BOS”), both of which are wealth management firms and registered investment advisers (together, the “Wealth Advisors” and, together with the Investment Managers, the “non-banks”). The Company conducts substantially all of its business through its three reportable segments. All significant intercompany accounts and transactions have been eliminated in consolidation. The unaudited interim consolidated financial statements of the Company have been prepared in accordance with accounting principles generally accepted in the United States (“GAAP”), and include all necessary adjustments of a normal recurring nature which, in the opinion of management, are required for a fair presentation of the results of operations and financial condition of the Company. The interim results of consolidated operations are not necessarily indicative of the results for the entire year. The information in this report should be read in conjunction with the consolidated financial statements and accompanying notes included in the Annual Report on Form 10-K for the year ended December 31, 2013, as filed with the Securities and Exchange Commission (“SEC”). Prior period amounts are reclassified whenever necessary to conform to the current period presentation. On January 1, 2014, the Company early adopted Accounting Standards Update (“ASU”) 2014-01 Investments - Equity Methods and Joint Ventures (Topic 323): Accounting for Investments in Qualified Affordable Housing Projects, (“ASU 2014-01”). As a result of adopting ASU 2014-01, amortization expense of these investments, which was previously reported as an operating expense, is now reported with income tax expense and is measured using the proportional amortization method. There was no change to the reporting of the related tax benefits from tax losses and credits, which have always been reported within income tax expense. ASU 2014-01 required retrospective adoption. Therefore, prior periods have been reclassified to conform to current period presentation. Included within income tax expense for the three months ending June 30, 2014 and 2013 is $0.1 million and $0.1 million, respectively, of amortization of investments and $0.3 million and $0.2 million, respectively, of related tax benefits from tax losses and credits. Included within income tax expense for the six months ending June 30, 2014 and 2013 is $0.4 million and $0.3 million, respectively, of amortization of investments and $0.5 million and $0.3 million, respectively, of related tax benefits from tax losses and credits. The Company’s significant accounting policies are described in Part II. Item 8. “Financial Statements and Supplementary Data - Note 1: Basis of Presentation and Summary of Significant Accounting Policies” in the Company’s Annual Report on Form 10-K for the year ended December 31, 2013, as filed with the SEC. For interim reporting purposes, the Company follows the same significant accounting policies.

Basis of Presentation and Summary of Significant Accounting Policies

Boston Private Financial Holdings, Inc. (the “Company” or “BPFH”), is a bank holding company (the “Holding Company”) with three reportable segments: Private Banking, Investment Management, and Wealth Advisory.

Boston Private Bank & Trust Company (the “Bank” or “Boston Private Bank”) is a trust company chartered by The Commonwealth of Massachusetts, insured by the Federal Deposit Insurance Corporation (the “FDIC”), and a wholly-owned subsidiary of the Company. Boston Private Bank currently operates in three geographic markets: New England, San Francisco Bay, and Southern California.

The Investment Management segment has two consolidated affiliates, consisting of Dalton, Greiner, Hartman, Maher & Co., LLC (“DGHM”) and Anchor Capital Advisors, LLC (“Anchor”), both of which are registered investment advisers (together, the “Investment Managers”).

The Wealth Advisory segment has two consolidated affiliates, consisting of KLS Professional Advisors Group, LLC (“KLS”) and Bingham, Osborn & Scarborough, LLC (“BOS”), both of which are wealth management firms and registered investment advisers (together, the “Wealth Advisors” and, together with the Investment Managers, the “non-banks”).

The Company conducts substantially all of its business through its three reportable segments. All significant intercompany accounts and transactions have been eliminated in consolidation.

The unaudited interim consolidated financial statements of the Company have been prepared in accordance with accounting principles generally accepted in the United States (“GAAP”), and include all necessary adjustments of a normal recurring nature which, in the opinion of management, are required for a fair presentation of the results of operations and financial condition of the Company. The interim results of consolidated operations are not necessarily indicative of the results for the entire year.

The information in this report should be read in conjunction with the consolidated financial statements and accompanying notes included in the Annual Report on Form 10-K for the year ended December 31, 2013, as filed with the Securities and Exchange Commission (“SEC”). Prior period amounts are reclassified whenever necessary to conform to the current period presentation.

On January 1, 2014, the Company early adopted Accounting Standards Update (“ASU”) 2014-01 Investments - Equity Methods and Joint Ventures (Topic 323): Accounting for Investments in Qualified Affordable Housing Projects, (“ASU 2014-01”). As a result of adopting ASU 2014-01, amortization expense of these investments, which was previously reported as an operating expense, is now reported with income tax expense and is measured using the proportional amortization method. There was no change to the reporting of the related tax benefits from tax losses and credits, which have always been reported within income tax expense. ASU 2014-01 required retrospective adoption. Therefore, prior periods have been reclassified to conform to current period presentation. Included within income tax expense for the three months ending June 30, 2014 and 2013 is $0.1 million and $0.1 million, respectively, of amortization of investments and $0.3 million and $0.2 million, respectively, of related tax benefits from tax losses and credits. Included within income tax expense for the six months ending June 30, 2014 and 2013 is $0.4 million and $0.3 million, respectively, of amortization of investments and $0.5 million and $0.3 million, respectively, of related tax benefits from tax losses and credits.

The Company’s significant accounting policies are described in Part II. Item 8. “Financial Statements and Supplementary Data - Note 1: Basis of Presentation and Summary of Significant Accounting Policies” in the Company’s Annual Report on Form 10-K for the year ended December 31, 2013, as filed with the SEC. For interim reporting purposes, the Company follows the same significant accounting policies.