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Investment, Carried at Cost - Additional Information (Detail) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016	Nov. 18, 2016
Schedule of Cost-method Investments [Line Items]
Cost method investments	$ 20,000,000	$ 20,000,000
Advisor Engine Inc. [Member]
Schedule of Cost-method Investments [Line Items]
Date of agreement	Nov. 18, 2016
Cost method investments			$ 20,000,000
Fully diluted ownership interest percentage	36.00%
Ownership interest percentage	42.00%
Impairment losses	$ 0	$ 0
Advisor Engine Inc. [Member] | Series A Preferred [Member]
Schedule of Cost-method Investments [Line Items]
Number of shares purchased	11,811,856
Advisor Engine Inc. [Member] | Series A Preferred [Member]
Schedule of Cost-method Investments [Line Items]
Non-cumulative dividend	6.00%

X

- Definition

Amount, after adjustment, of cost-method investment. Adjustments include, but are not limited to, dividends received in excess of earnings after date of investment that are considered a return of investment and other than temporary impairments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.12)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 325
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6872867&loc=d3e40691-111596

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 325
-SubTopic 20
-Section 35
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=29638308&loc=d3e40346-111594

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- Definition

This item represents an other than temporary decline in value that has been recognized against an investment accounted for under the cost method of accounting. The excess of the carrying amount over the fair value of the investment represents the amount of the write down which is or was reflected in earnings. The written down value is a new cost basis with the adjusted value of the investment becoming its new carrying value. Evidence of a loss in value might include, but would not necessarily be limited to, absence of an ability to recover the carrying amount of the investment or inability of the investee to sustain an earnings capacity which would justify the carrying amount of the investment.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 325
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6872867&loc=d3e40691-111596

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- Definition

The percentage rate used to calculate dividend payments on preferred stock.

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- Definition

Fully diluted ownership interest percentage.

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- Definition

Investment agreement date.

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- Definition

Number of shares purchased from related parties.

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Percentage of ownership interest related parties.

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