Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Statement of Comprehensive Income [Abstract]
Net income	$ 19,606	$ 46,058
Unrealized holding gains:
Before tax	62,554	26,752
Tax effect	(17,297)	(7,451)
Net of tax	45,257	19,301
Reclassification of net losses included in net income:
Before tax	1,005	0
Tax effect	(282)	0
Net of tax	723	0
Net unrealized holding gains	44,534	19,301
Derivative Instruments
Before tax	(10,040)	1,458
Tax effect	2,783	(406)
Net of tax	(7,257)	1,052
Total other comprehensive income	37,277	20,353
Total comprehensive income	$ 56,883	$ 66,411