Investments - Schedule of Amortized Cost and Fair Value on Mortgage-Backed and Asset-Backed Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 815,647	$ 828,336
Fair Value	819,861	855,284
Mortgage-backed and asset-backed securities [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	319,377	304,285
Fair Value	319,937	311,079
Agency [Member] | Mortgage-backed securities [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	153,937	143,723
Fair Value	153,758	144,729
Non-agency [Member] | Mortgage-backed securities [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	54,231	71,140
Fair Value	54,666	75,896
Auto loan receivables [Member] | Asset-backed securities [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	68,188	42,767
Fair Value	68,440	43,127
Credit card receivables [Member] | Asset-backed securities [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	7,878	21,145
Fair Value	7,891	21,487
Other receivables [Member] | Asset-backed securities [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	35,143	25,510
Fair Value	$ 35,182	$ 25,840