Securities Available for Sale - Continuous loss (Details) $ in Thousands	Sep. 30, 2018 USD ($) position	Dec. 31, 2017 USD ($) position
Debt Securities, Available-for-sale [Line Items]
Fair Value, Less than 12 months	$ 54,610	$ 45,303
Unrealized Losses, Less than 12 months	(187)	(58)
Fair Value, 12 months or longer	0	0
Unrealized Losses, 12 months or longer	0	0
Fair Value	54,610	45,303
Unrealized Losses	$ (187)	$ (58)
Number of positions with unrealized losses \| position	34	24
Asset-backed senior securities related to Company-sponsored securitizations (1)
Debt Securities, Available-for-sale [Line Items]
Fair Value, Less than 12 months	$ 44,930	$ 26,534
Unrealized Losses, Less than 12 months	(183)	(46)
Fair Value, 12 months or longer	0	0
Unrealized Losses, 12 months or longer	0	0
Fair Value	44,930	26,534
Unrealized Losses	(183)	(46)
Asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Fair Value, Less than 12 months	5,796	4,401
Unrealized Losses, Less than 12 months	(1)	(1)
Fair Value, 12 months or longer	0	0
Unrealized Losses, 12 months or longer	0	0
Fair Value	5,796	4,401
Unrealized Losses	(1)	(1)
Corporate debt securities
Debt Securities, Available-for-sale [Line Items]
Fair Value, Less than 12 months	3,386	14,368
Unrealized Losses, Less than 12 months	(3)	(11)
Fair Value, 12 months or longer	0	0
Unrealized Losses, 12 months or longer	0	0
Fair Value	3,386	14,368
Unrealized Losses	(3)	$ (11)
Other securities
Debt Securities, Available-for-sale [Line Items]
Fair Value, Less than 12 months	498
Unrealized Losses, Less than 12 months	0
Fair Value, 12 months or longer	0
Unrealized Losses, 12 months or longer	0
Fair Value	498
Unrealized Losses	$ 0

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 7
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