Related Party Transactions - GAP Waiver Insurance Policy (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Related Party Transaction [Line Items]
Other assets, due from related parties	$ 14,850	$ 13,098
Related Party | BlueShore
Related Party Transaction [Line Items]
Payments to acquire GAP waiver insurance policy	1,800
Other assets, due from related parties	$ 200