STOCKHOLDERS' EQUITY - Common Stock (Details) - shares	3 Months Ended	9 Months Ended
Sep. 30, 2019	Sep. 30, 2019
Stockholders' Equity Note [Abstract]
Common stock shares issued in public or private offerings	0	0

Represents the common shares sold by the entity in a private placement pursuant to the agreement.

No definition available.

Name:	acre_CommonStockSubscriptionAgreementSharesIssued
Namespace Prefix:	acre_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration