Goodwill and Intangible Assets - Changes in Goodwill (Details) - USD ($) $ in Thousands	9 Months Ended
	Jun. 30, 2018	Sep. 30, 2017
Goodwill [Roll Forward]
Goodwill, beginning	$ 58,517
Goodwill attributable to the acquisitions of SDCR, Inc., CS, LLC and EMS, Inc.	21,649
Goodwill, ending	80,166
Merchant Services
Goodwill [Roll Forward]
Goodwill, beginning	49,173
Goodwill attributable to the acquisitions of SDCR, Inc., CS, LLC and EMS, Inc.	20,368
Goodwill, ending	69,541
Accumulated impairment losses		$ 11,458
Other
Goodwill [Roll Forward]
Goodwill, beginning	9,344
Goodwill attributable to the acquisitions of SDCR, Inc., CS, LLC and EMS, Inc.	1,281
Goodwill, ending	$ 10,625
Accumulated impairment losses		$ 0