Revenue and Related Matters (Q3) (Tables)

9 Months Ended

12 Months Ended

Sep. 30, 2021

Dec. 31, 2020

Revenue from Contract with Customers [Abstract]

Schedule of Principal Activities From Which the Company Generates Revenue

The Company disaggregates revenue as set forth in the following table (in thousands):

Revenue by Type

	Three Months Ended September 30,				Nine Months Ended September 30,
Revenues:	2021		2020		2021		2020
Subscription and transaction fees	$	30,376	$	26,130	$	89,631	$	73,065
Services and other		2,356		2,678		7,809		5,913
Subscription, transaction, and services	$	32,732	$	28,808	$	97,440	$	78,978

The following is a description of principal activities from which the Company generates revenue, as well as a further breakdown of the components of subscription, transaction and services revenues for each year ended December 31:

	2020		2019		2018
Subscription and transaction fees	$	99,609	$	89,476	$	74,725
Services and other		8,960		6,984		4,846
Subscription, transaction and services	$	108,569	$	96,460	$	79,571