Investments Maturities of AFS Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Amortized Cost
Within one year	$ 33,686
After one, but within five years	312,665
After five, but within ten years	230,955
Greater than ten years	384,045
Amortized Cost	961,351	$ 966,900
Fair Value
Within one year	33,916
After one, but within five years	322,256
After five, but within ten years	239,899
Greater than ten years	397,095
Total	$ 993,166	$ 978,284