Related party transactions - Deposits with PRLP 2011 Holdings, LLC and PR Asset Portfolio 2013-1 International, LLC (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
PRLP 2011 Holding, LLC
Related Party Transaction [Line Items]
Deposits	$ (909)	$ (2,566)
PR Asset Portfolio 2013-1 International, LLC
Related Party Transaction [Line Items]
Deposits	$ (9,582)	$ (7,994)

Amount of deposits held by the entity for a related party (entity, shareholder, employee).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(k))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Name:	us-gaap_RelatedPartyDepositLiabilities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant