Revenue from Contracts with Customers (Schedule of Revenue from Contracts with Customers) (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Fee revenue and other income:
In-scope of FASB ASC 606 - Invoice processing fees		$ 20,408	$ 19,876	$ 61,397	$ 58,492
In-scope of FASB ASC 606 - Invoice payment fees		7,333	6,144	19,653	17,576
Information services payment and processing revenue		27,741	26,020	81,050	76,068
Bank service fees		307	300	984	994
Fee revenue (in-scope of FASB ASC 606)		28,048	26,320	82,034	77,062
Other income (out-of-scope of FASB ASC 606)		214	115	613	387
Total fee revenue and other income		28,262	26,435	82,647	77,449
Net interest income after provision for loan losses (out-of-scope of FASB ASC 606)	[1]	12,274	11,186	35,653	32,514
Total net revenue		$ 40,536	$ 37,621	$ 118,300	$ 109,963

[1] The Company earns interest income from the balances generated during the invoice processing and payment cycle and on deposit accounts, which is an integral component of the Company’s compensation for services provided, but is out-of-scope of FASB ASC 606.