XML 23 R47.htm IDEA: XBRL DOCUMENT
v3.20.1

Stockholders' Equity - Dividends Declared (Details) - $ / shares | 3 Months Ended
--- | ---
Mar. 31, 2020 | Mar. 31, 2019
Dividends Declared [Line Items] |  |
Dividends declared per Class A common share (in dollars per share) | $ 1.28 | $ 1.59
Quarterly |  |
Dividends Declared [Line Items] |  |
Dividends declared per Class A common share (in dollars per share) | 0.68 | 0.56
Special Annual |  |
Dividends Declared [Line Items] |  |
Dividends declared per Class A common share (in dollars per share) | $ 0.60 | $ 1.03

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 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_DividendsPayableLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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: |