Junior Subordinated Debentures (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Debt Instrument [Line Items]
Junior subordinated debentures	$ 106,363	$ 143,647
Boston Private Capital Trust II [Member]
Debt Instrument [Line Items]
Junior subordinated debentures	103,093	103,093
Boston Private Capital Trust I [Member]
Debt Instrument [Line Items]
Junior subordinated debentures	3,270	13,749
Gibraltar Financial Statutory Trust I [Member]
Debt Instrument [Line Items]
Junior subordinated debentures	0	16,495
First State (CA) Statutory Trust I [Member]
Debt Instrument [Line Items]
Junior subordinated debentures	0	6,186
Charter Financial Trust I [Member]
Debt Instrument [Line Items]
Junior subordinated debentures	$ 0	$ 4,124

Including the current and noncurrent portions, the carrying value of junior subordinated long-term debt owed to unconsolidated subsidiary trusts as of the balance sheet date. Such debt places a lender in a lien position behind debt having a higher priority of repayment in liquidation of the entity's assets and was initially scheduled to be repaid after one year or beyond the normal operating cycle if longer.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.16)

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 16

-Article 9

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.16)

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Name:	us-gaap_JuniorSubordinatedDebentureOwedToUnconsolidatedSubsidiaryTrust
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant