Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Statement of Comprehensive Income [Abstract]
Net Income	$ 38,908	$ 56,919	$ 73,650	$ 115,718
Other Comprehensive Income (Loss), Net of Tax:
Net Unrealized Gains (Losses) on Investment Securities	7,730	16,209	49,289	23,128
Defined Benefit Plans	374	245	748	491
Total Other Comprehensive Income (Loss)	8,104	16,454	50,037	23,619
Comprehensive Income	$ 47,012	$ 73,373	$ 123,687	$ 139,337