XML 59 R48.htm IDEA: XBRL DOCUMENT v3.19.2

Stockholders' Equity (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2019 vote $ / shares shares	Jun. 30, 2018 $ / shares	Jun. 30, 2019 vote $ / shares shares	Jun. 30, 2018 $ / shares	Dec. 31, 2018 $ / shares shares
Class of Stock [Line Items]
Unvested - Number of awards (in shares)	5,151,157		5,151,157		4,678,457
Common Stock, Shares, Outstanding	77,814,721		77,814,721		76,942,872
Dividends declared per Class A common share (in dollars per share) | $ / shares	$ 0.55	$ 0.60	$ 2.14	$ 1.99
Holdings GP Units
Class of Stock [Line Items]
Common Stock, Shares, Outstanding					54,071,188
Class A Common Stock
Class of Stock [Line Items]
Common stock, shares authorized (in shares)	500,000,000		500,000,000		500,000,000
Common Stock, Shares, Outstanding	56,145,554		56,145,554		54,071,188
Common stock votes per share | vote	1		1
Common stock, par value per share (in dollars per share) | $ / shares	$ 0.01		$ 0.01		$ 0.01
Class B Common Stock
Class of Stock [Line Items]
Common stock, shares authorized (in shares)	200,000,000		200,000,000		200,000,000
Common Stock, Shares, Outstanding	7,912,056		7,912,056		8,645,249
Common stock votes per share | vote	1		1
Common stock, par value per share (in dollars per share) | $ / shares	$ 0.01		$ 0.01		$ 0.01
Class C Common Stock
Class of Stock [Line Items]
Common stock, shares authorized (in shares)	400,000,000		400,000,000		400,000,000
Common Stock, Shares, Outstanding	13,757,111		13,757,111		14,226,435
Common stock votes per share | vote	1		1
Common stock, par value per share (in dollars per share) | $ / shares	$ 0.01		$ 0.01		$ 0.01
Restricted Stock | Holdings GP Units
Class of Stock [Line Items]
Unvested - Number of awards (in shares)	5,044,032		5,044,032
Restricted Stock Units (RSUs)
Class of Stock [Line Items]
Restricted stock units outstanding (in shares)	297,891		297,891		246,581
Quarterly
Class of Stock [Line Items]
Dividends declared per Class A common share (in dollars per share) | $ / shares	$ 0.55	0.60	$ 1.11	1.20
Special Annual
Class of Stock [Line Items]
Dividends declared per Class A common share (in dollars per share) | $ / shares	$ 0	$ 0	$ 1.03	$ 0.79

X

- Definition

Common Stock Number of Votes per Share

+ References

No definition available.

+ Details

Name:	apam_CommonStockNumberofVotes_per_Share
Namespace Prefix:	apam_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_ClassOfStockLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Aggregate dividends paid during the period for each share of common stock outstanding.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

+ Details

Name:	us-gaap_CommonStockDividendsPerShareCashPaid
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Face amount or stated value per share of common stock.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_CommonStockParOrStatedValuePerShare
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

X

- Definition

The maximum number of common shares permitted to be issued by an entity's charter and bylaws.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_CommonStockSharesAuthorized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Number of shares of common stock outstanding. Common stock represent the ownership interest in a corporation.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_CommonStockSharesOutstanding
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

X

- Definition

The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(i)-(ii)
-URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Number of equity instruments other than options outstanding, including both vested and non-vested instruments.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(ii)
-URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(i)
-URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingNumber
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

X

- Details

Name:	us-gaap_StatementClassOfStockAxis=apam_GeneralPartnershipUnitsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_StatementClassOfStockAxis=us-gaap_CommonClassAMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_StatementClassOfStockAxis=us-gaap_CommonClassBMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_StatementClassOfStockAxis=us-gaap_CommonClassCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_AwardTypeAxis=us-gaap_RestrictedStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_AwardTypeAxis=us-gaap_RestrictedStockUnitsRSUMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DividendsAxis=apam_QuarterlyCashDividendMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DividendsAxis=apam_SpecialAnnualDividendMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: