Boston Private Financial Holdings, Inc. (Parent Company Only) Balance Sheet (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011	Dec. 31, 2010
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	$ 191,881		$ 308,744		$ 203,354	$ 493,433
Deferred income taxes, net	69,065		73,414
Other assets	118,045		124,956
Assets	6,437,109		6,465,005		6,049,372
Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust	106,363		143,647
Other liabilities	97,613		95,386
Total liabilities	5,783,953		5,842,616
Redeemable noncontrolling interests	19,468		19,287		21,691	19,598
Stockholders' Equity Attributable to Parent	633,517		603,102
Total liabilities, redeemable noncontrolling interests and shareholders’ equity	6,437,109		6,465,005
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	32,554		61,221		96,871	88,463
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	6,340		7,143
Deferred income taxes, net	2,209		19,092
Other assets	20,267		18,273
Assets	777,097		785,315
Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust	106,363		143,647
Other liabilities	17,578		19,279
Total liabilities	123,941		162,926
Redeemable noncontrolling interests	19,639	[1]	19,287	[1]
Stockholders' Equity Attributable to Parent	633,517		603,102
Total liabilities, redeemable noncontrolling interests and shareholders’ equity	777,097		785,315
Parent Company [Member] | Private Banking Segment [Member]
Condensed Financial Statements, Captions [Line Items]
Investments in and Advances to Affiliates, Balance, Principal Amount	573,426		544,160
Parent Company [Member] | Non Banking Segments [Member]
Condensed Financial Statements, Captions [Line Items]
Investments in and Advances to Affiliates, Balance, Principal Amount	$ 142,301		$ 135,426

[1] Represents the maximum redemption value of noncontrolling interests.