Borrowings - Obligations Under Capital Lease (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Borrowings
Average balance	$ 13,498	$ 24,830	$ 18,620
Weighted average interest rate	3.96%	3.07%	2.47%
Total interest expense	$ 536	$ 769	$ 510
Maximum daily amount outstanding	20,971	30,044	$ 24,242
Unpaid principal balance	$ 6,605	$ 20,971
Weighted average interest rate	4.46%	3.26%
Furniture, fixtures, equipment and building improvements pledged to creditors	$ 16,281	$ 23,915
Capitalized software pledged to creditors	$ 1,017	$ 1,568