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, Before-tax Amount	$ 243,014	$ 124,058	$ 479,267	$ 166,173
Net income, Tax Effect	(56,814)	(30,866)	(105,975)	(34,461)
Net income	186,200	93,192	373,292	131,712
Net unrealized gains (losses) on investment securities available for sale: Before-tax Amount
Net unrealized holding gains (losses) arising during the period, Before-tax Amount	46,342	(11,939)	(118,899)	146,403
Reclassification adjustment for net losses realized in net income, Before-tax Amount	0	(69,409)	1,990	(78,144)
Net unrealized gains (losses), Before-tax Amount	46,342	(81,348)	(116,909)	68,259
Net unrealized gains (losses) on investment securities available for sale: Tax Effect
Net unrealized holding gains (losses) arising during the period, Tax Effect	(11,725)	3,092	31,056	(37,919)
Reclassification adjustment for net losses realized in net income, Tax Effect	0	17,977	(515)	20,239
Net unrealized gains (losses), Tax Effect	(11,725)	21,069	30,541	(17,680)
Net unrealized gains (losses) on investment securities available for sale: Net of Tax Amount
Net unrealized holding gains (losses) arising during the period, Net of Tax Amount	34,617	(8,847)	(87,843)	108,484
Reclassification adjustment for net losses realized in net income, Net of Tax Amount	0	(51,432)	1,475	(57,905)
Net unrealized gains (losses), Net of Tax Amount	34,617	(60,279)	(86,368)	50,579
Unrealized gains (losses) on derivative instruments designated as cash flow hedges, Before-tax Amount
Net unrealized gains (losses) arising during the period, Before-tax Amount	(1,923)	8,823	(30,980)	117,462
Reclassification adjustment for realized (gains) losses included in net income, Before-tax Amount	(3,657)	(270)	(5,256)	(390)
Net change, Before-tax Amount	(5,580)	8,553	(36,236)	117,072
Unrealized gains (losses) on derivative instruments designated as cash flow hedges, Tax Effect
Net unrealized gains (losses) arising during the period, Income Tax	486	(2,285)	8,360	(30,423)
Reclassification adjustment for realized (gains) losses included in net income, Income Tax	925	70	1,335	101
Net change, Income Tax	1,411	(2,215)	9,695	(30,322)
Unrealized gains (losses) on derivative instruments designated as cash flow hedges, Net of Tax Amount
Net unrealized gains (losses) arising during the period, Net of Tax Amount	(1,437)	6,538	(22,620)	87,039
Reclassification adjustment for realized (gains) losses included in net income, Net of Tax Amount	(2,732)	(200)	(3,921)	(289)
Net change, Net of Tax Amount	(4,169)	6,338	(26,541)	86,750
Other comprehensive income (loss), Before-tax Amount	40,762	(72,795)	(153,145)	185,331
Other comprehensive income (loss), Tax Effect	(10,314)	18,854	40,236	(48,002)
Other comprehensive income (loss), Net of Tax	30,448	(53,941)	(112,909)	137,329
Comprehensive income, Net of Tax Amount	$ 216,648	$ 39,251	$ 260,383	$ 269,041