Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Cash flows from operating activities:
Net earnings	$ 240,729	$ 234,011
Depreciation and amortization	18,607	17,512
Amortization of net premiums on securities available-for-sale	7,933	14,164
Amortization of intangible assets	9,740	11,933
Amortization of operating lease ROU assets	14,723	0
Provision for credit losses	12,000	21,500
(Gain) loss on sale of foreclosed assets	(320)	35
Provision for losses on foreclosed assets	0	65
Gain on sale of loans and leases	(326)	(4,675)
Gain on sale of premises and equipment	(37)	(8)
Gain on sale of securities	(24,353)	(6,564)
Gain on BOLI death benefit	0	(387)
Unrealized (gain) loss on derivatives and foreign currencies, net	(40)	20
Earned stock compensation	12,529	14,745
Decrease (increase) in deferred income taxes, net	14,714	(1,640)
Decrease in other assets	29,635	53,534
Decrease in accrued interest payable and other liabilities	(55,550)	(47,696)
Net cash provided by operating activities	279,984	306,549
Cash flows from investing activities:
Net increase in loans and leases	(605,228)	(95,306)
Proceeds from sales of loans and leases	80,440	643,261
Proceeds from maturities and paydowns of securities available-for-sale	150,766	157,806
Proceeds from sales of securities available-for-sale	1,410,510	368,775
Purchases of securities available-for-sale	(1,232,214)	(708,167)
Net purchases of Federal Home Loan Bank stock	(11,043)	(5,481)
Proceeds from sales of foreclosed assets	4,184	57
Proceeds from sales of premises and equipment	54	32
Proceeds from BOLI death benefit	555	313
Purchases of premises and equipment, net	(8,621)	(7,332)
Net (increase) decrease in equipment leased to others under operating leases	(18,986)	7,746
Net cash (used in) provided by investing activities	(229,583)	361,704
Cash flows from financing activities:
Net decrease in noninterest-bearing deposits	(588,417)	(379,436)
Net increase (decrease) in interest-bearing deposits	524,957	(554,453)
Net increase in borrowings	541,945	719,884
Net decrease in subordinated debentures	0	(12,372)
Common stock repurchased and restricted stock surrendered	(161,826)	(249,007)
Cash dividends paid	(145,089)	(139,741)
Net cash provided by (used in) financing activities	171,570	(615,125)
Net increase in cash, cash equivalents, and restricted cash	221,971	53,128
Cash, cash equivalents, and restricted cash, beginning of period	385,767	398,437
Cash, cash equivalents, and restricted cash, end of period	607,738	451,565
Supplemental disclosures of cash flow information:
Cash paid for interest	97,238	47,569
Cash paid for income taxes	68,305	23,273
Loans transferred to foreclosed assets	37	1,059
Transfers from loans held for investment to loans held for sale	$ 25,124	$ 0