Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130543-203045

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130545-203045

Name:	us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Major Customer (Details) - USD ($) $ in Thousands	3 Months Ended		8 Months Ended	9 Months Ended
Major Customer (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Government servicing - Nelnet
Concentration Risk [Line Items]
Revenue	$ 38,645	$ 38,907		$ 118,744	$ 118,015
Government servicing - Nelnet \| Customer concentration risk
Concentration Risk [Line Items]
Revenue	38,600	38,900		118,700	118,000
Government servicing - Great Lakes
Concentration Risk [Line Items]
Revenue	46,234	45,671		139,285	$ 122,107
Government servicing - Great Lakes \| Customer concentration risk
Concentration Risk [Line Items]
Revenue	$ 46,200	$ 45,700	$ 122,100	$ 139,300