Fair Value - Level 3 Assets (Details) - Level 3 - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Roll forward of level 3 fair value measurements on a recurring basis
Beginning balance	$ 23,785	$ 19,439	$ 26,224	$ 11,645
Included in earnings	(86)	(61)	(178)	(62)
Included in other comprehensive income	24	1,147	(370)	(379)
Purchases	5,865	8,741	9,440	10,771
Sales	(1,521)	(316)	(2,157)	(829)
Transfers into Level 3	7,001	5,476	10,523	16,928
Transfers out of Level 3	(4,522)	(10,390)	(12,936)	(14,038)
Ending balance	30,546	24,036	30,546	24,036
Available-for-sale securities
Roll forward of level 3 fair value measurements on a recurring basis
Beginning balance	22,695	19,439	26,224	11,645
Included in earnings	(91)	(36)	(183)	(37)
Included in other comprehensive income	24	1,147	(370)	(379)
Purchases	4,865	7,921	8,440	9,951
Sales	(1,521)	(316)	(2,157)	(829)
Transfers into Level 3	7,001	5,476	9,433	16,928
Transfers out of Level 3	(3,427)	(10,390)	(11,841)	(14,038)
Ending balance	29,546	23,241	29,546	23,241
Corporate debt securities | Available-for-sale securities
Roll forward of level 3 fair value measurements on a recurring basis
Beginning balance	5,460	12,056	5,825	8,324
Included in earnings	14	(2)	20	5
Included in other comprehensive income	37	867	79	(511)
Purchases	1,476	783	2,258	2,501
Sales	(303)	(115)	(673)	(542)
Transfers into Level 3	1,347	1,142	2,549	8,037
Transfers out of Level 3	(1,953)	(9,815)	(3,980)	(12,898)
Ending balance	6,078	4,916	6,078	4,916
Collateralized debt obligations | Available-for-sale securities
Roll forward of level 3 fair value measurements on a recurring basis
Beginning balance	0	0	0	0
Included in earnings	0	0	0	0
Included in other comprehensive income	0	12	0	12
Purchases	750	247	750	247
Sales	0	0	0	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Ending balance	750	259	750	259
Commercial mortgage-backed securities | Available-for-sale securities
Roll forward of level 3 fair value measurements on a recurring basis
Beginning balance	16,241	7,383	19,462	3,321
Included in earnings	(102)	(34)	(197)	(42)
Included in other comprehensive income	(10)	268	(447)	120
Purchases	579	6,891	2,844	7,203
Sales	(961)	(201)	(966)	(287)
Transfers into Level 3	2,624	4,334	3,854	8,891
Transfers out of Level 3	(1,238)	(575)	(7,417)	(1,140)
Ending balance	17,133	18,066	17,133	18,066
Residential mortgage-backed securities | Available-for-sale securities
Roll forward of level 3 fair value measurements on a recurring basis
Beginning balance	473		937
Included in earnings	(3)		(6)
Included in other comprehensive income	1		0
Purchases	0		0
Sales	(224)		(476)
Transfers into Level 3	3,030		3,030
Transfers out of Level 3	(236)		(444)
Ending balance	3,041		3,041
Other debt securities | Available-for-sale securities
Roll forward of level 3 fair value measurements on a recurring basis
Beginning balance	521		0
Included in earnings	0		0
Included in other comprehensive income	(4)		(2)
Purchases	2,060		2,588
Sales	(33)		(42)
Transfers into Level 3	0		0
Transfers out of Level 3	0		0
Ending balance	2,544		2,544
Nonredeemable preferred stock | Nonredeemable preferred stock
Roll forward of level 3 fair value measurements on a recurring basis
Beginning balance	1,090	0	0	0
Included in earnings	5	(25)	5	(25)
Included in other comprehensive income	0	0	0	0
Purchases	1,000	820	1,000	820
Sales	0	0	0	0
Transfers into Level 3	0	0	1,090	0
Transfers out of Level 3	(1,095)	0	(1,095)	0
Ending balance	$ 1,000	$ 795	$ 1,000	$ 795