Revenue from Contracts with Customers (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Revenue, Performance Obligation [Abstract]
Fee revenues, in-scope of FASB ASC 606	$ 27,410	$ 24,817	$ 79,998	$ 73,789
Other income (out-of-scope of FASB ASC 606)	167	115	741	1,412
Total fee revenue and other income	27,577	24,932	80,739	75,201
Information services payment and processing revenue
Revenue, Performance Obligation [Abstract]
Fee revenues, in-scope of FASB ASC 606	26,877	24,376	78,441	72,540
Invoice processing fees
Revenue, Performance Obligation [Abstract]
Fee revenues, in-scope of FASB ASC 606	19,230	18,650	58,047	55,697
Invoice payment fees
Revenue, Performance Obligation [Abstract]
Fee revenues, in-scope of FASB ASC 606	7,647	5,726	20,394	16,843
Bank service fees
Revenue, Performance Obligation [Abstract]
Fee revenues, in-scope of FASB ASC 606	$ 533	$ 441	$ 1,557	$ 1,249