Student Loans - Narrative (Details)	3 Months Ended								12 Months Ended
	Dec. 31, 2018 USD ($) loan	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($) loan	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2018 USD ($) loan	Dec. 31, 2017 USD ($) loan	Dec. 31, 2016 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Installment loans, consumer, student	$ 68,221,000				$ 59,853,000				$ 68,221,000	$ 59,853,000
Interest Receivable	8,341,000				6,526,000				8,341,000	6,526,000
Allowance for losses	8,395,000				9,267,000				8,395,000	9,267,000	$ 8,902,000
TDRs	7,059,000				11,362,000				7,059,000	11,362,000	12,410,000
Accrued interest receivable, charged against interest income	(8,945,000)	$ (8,863,000)	$ (7,778,000)	$ (8,326,000)	(8,144,000)	$ (8,157,000)	$ (7,672,000)	$ (7,228,000)	(33,912,000)	(31,200,000)	$ (28,064,000)
Student loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest Receivable	$ 5,984,000				$ 4,261,000				$ 5,984,000	$ 4,261,000
Number of loans | loan	1,674				1,554				1,674	1,554
Allowance for losses	$ 1,520,000				$ 772,000				$ 1,520,000	$ 772,000
TDRs	0				0				0	0
Charge-off of loans									388,000
Accrued interest receivable, charged against interest income									26,000
Student loan | Not yet entered repayment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest Receivable	$ 5,494,000				$ 4,261,000				$ 5,494,000	$ 4,261,000
Student loan | Repayment, Deferment, and Forbearance [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of loans | loan	595				180				595	180
Student loan | Repayment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest Receivable	$ 118,000				$ 40,000				$ 118,000	$ 40,000
Number of loans | loan	366				201				366	201
Loans outstanding	$ 15,526,000				$ 6,473,000				$ 15,526,000	$ 6,473,000
Student loan | Deferment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest Receivable	$ 79,000				$ 45,000				$ 79,000	$ 45,000
Number of loans | loan	48				32				48	32
Loans outstanding	$ 1,945,000				$ 1,128,000				$ 1,945,000	$ 1,128,000
Student loan | Forbearance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest Receivable	$ 212,000				$ 37,000				$ 212,000	$ 37,000
Number of loans | loan	181				50				181	50
Loans outstanding	$ 7,336,000				$ 1,981,000				$ 7,336,000	$ 1,981,000
General reserve | Student loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for losses	880,000								880,000
ReliaMax Surety Company Insolvency | Student loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for losses	$ 640,000								$ 640,000