Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Statement of Comprehensive Income [Abstract]
Net income	$ 51,121	$ 19,064	$ 96,144	$ 38,670
Unrealized holding gains (losses):
Before tax	24,603	(1,719)	(40,542)	60,835
Tax effect	(6,793)	381	11,180	(16,916)
Net of tax	17,810	(1,338)	(29,362)	43,919
Reclassification of net losses included in net income:
Before tax	0	0	0	(1,005)
Tax effect	0	0	0	282
Net of tax	0	0	0	(723)
Net unrealized holding gains (losses)	17,810	(1,338)	(29,362)	43,196
Unrealized holding losses:
Before tax	(2,287)	(7,300)	(4,082)	(17,340)
Tax effect	632	2,042	1,124	4,825
Net of tax	(1,655)	(5,258)	(2,958)	(12,515)
Total other comprehensive income (loss)	16,155	(6,596)	(32,320)	30,681
Total comprehensive income (loss)	$ 67,276	$ 12,468	$ 63,824	$ 69,351