Business acquisition date.

No definition available.

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- Definition

Date when the business acquisition agreement was executed, in CCYY-MM-DD format.

+ References

No definition available.

+ Details

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Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Date when the acquirer obtains control of the acquiree, in CCYY-MM-DD format.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 10

-Section 25

-Paragraph 6

-URI http://asc.fasb.org/extlink&oid=34752592&loc=d3e845-128460

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Acquisition Date

-URI http://asc.fasb.org/extlink&oid=6919109

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 10

-Section 25

-Paragraph 7

-URI http://asc.fasb.org/extlink&oid=34752592&loc=d3e848-128460

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=25497992&loc=d3e1392-128463

+ Details

Name:	us-gaap_BusinessAcquisitionEffectiveDateOfAcquisition1
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Balance Type:	na
Period Type:	duration

- Definition

Value of equity interests (such as common shares, preferred shares, or partnership interest) issued or issuable to acquire the entity.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 30

-Section 50

-Paragraph 1

-Subparagraph (b)(4)

-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479

+ Details

Name:	us-gaap_BusinessAcquisitionEquityInterestIssuedOrIssuableValueAssigned
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Number of shares of equity interests issued or issuable to acquire entity.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_BusinessAcquisitionLineItems
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Balance Type:	na
Period Type:	duration

- Definition

Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 30

-Section 30

-Paragraph 7

-URI http://asc.fasb.org/extlink&oid=6911251&loc=d3e6578-128477

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 30

-Section 30

-Paragraph 8

-URI http://asc.fasb.org/extlink&oid=6911251&loc=d3e6613-128477

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 30

-Section 50

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479

+ Details

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Balance Type:	credit
Period Type:	duration

- Definition

Amount of liability recognized arising from contingent consideration in a business combination, expected to be settled beyond one year or the normal operating cycle, if longer.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 30

-Section 25

-Paragraph 6

-URI http://asc.fasb.org/extlink&oid=6911189&loc=d3e6408-128476

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 30

-Section 35

-Paragraph 1

-Subparagraph b

-URI http://asc.fasb.org/extlink&oid=6911338&loc=d3e6819-128478

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13770-109266

+ Details

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- Details

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- Details

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- Details

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Acquisitions - Additional Information (Detail) (USD $) Share data in Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Business Acquisition [Line Items]
Business acquisition, contingent cash consideration	$ 34,000,000
Goodwill related to acquisition	392,570,000us-gaap_Goodwill	163,339,000us-gaap_Goodwill	164,874,000us-gaap_Goodwill
Limited Partnership Units [Member]
Business Acquisition [Line Items]
Business acquisition, equity interest issued, number of shares	1.2
Financial Services [Member]
Business Acquisition [Line Items]
Total consideration transferred	50,500,000
Business acquisition, contingent cash consideration	1,700,000
Goodwill related to acquisition	134,898,000	85,163,000	85,005,000
Financial Services [Member] \| Class A Common Stock [Member]
Business Acquisition [Line Items]
Business acquisition, equity interest issued, number of shares	0.3
Business acquisition, equity interest issued, fair value	2,700,000
Financial Services [Member] \| Limited Partnership Units [Member]
Business Acquisition [Line Items]
Business acquisition, equity interest issued, number of shares	1.3
Business acquisition, equity interest issued, fair value	6,200,000
Financial Services [Member] \| Heat Energy Group, LLC [Member]
Business Acquisition [Line Items]
Acquisition date	Feb. 14, 2014
Financial Services [Member] \| Remate Lince [Member]
Business Acquisition [Line Items]
Acquisition date	May 09, 2014
Financial Services [Member] \| Rp Martin Group [Member]
Business Acquisition [Line Items]
Business acquisition date	Dec. 12, 2014
Financial Services [Member] \| Heat Energy Group, LLC, Remate Lince and RP Martin Group [Member]
Business Acquisition [Line Items]
Goodwill related to acquisition	45,000,000
Real Estate Services [Member]
Business Acquisition [Line Items]
Total consideration transferred	201,900,000
Business acquisition, contingent cash consideration	32,300,000
Goodwill related to acquisition	257,672,000	78,176,000	79,869,000
Real Estate Services [Member] \| Class A Common Stock [Member]
Business Acquisition [Line Items]
Business acquisition, equity interest issued, fair value	13,100,000
Real Estate Services [Member] \| Class A Common Stock [Member] \| Restricted Shares [Member]
Business Acquisition [Line Items]
Business acquisition, equity interest issued, number of shares	1.7
Real Estate Services [Member] \| Limited Partnership Units [Member]
Business Acquisition [Line Items]
Business acquisition, equity interest issued, number of shares	3.6
Business acquisition, equity interest issued, fair value	28,000,000
Real Estate Services [Member] \| Cornish And Carey Commercial [Member]
Business Acquisition [Line Items]
Business acquisition date	Aug. 13, 2014
Real Estate Services [Member] \| Apartment Realty Advisors ("ARA") [Member]
Business Acquisition [Line Items]
Acquisition date	2014-12
Real Estate Services [Member] \| Cornish & Carey Commercial and Apartment Realty Advisors [Member]
Business Acquisition [Line Items]
Goodwill related to acquisition	$ 180,600,000