Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Cash flows from operating activities:
Net earnings	$ 350,298	$ 273,781
Depreciation and amortization	25,788	23,798
Amortization of net premiums on securities available-for-sale	19,489	30,238
Amortization of intangible assets	17,520	9,178
Provision for credit losses	33,000	51,346
Loss (gain) on sale of foreclosed assets	35	(282)
Provision for losses on foreclosed assets	65	2,138
Gain on sale of loans and leases	(4,675)	(4,209)
Gain on sale of premises and equipment	(13)	(388)
Gain on sale of securities	(7,390)	(2,788)
Gain on BOLI death benefit	(437)	(1,050)
Unrealized loss (gain) on derivatives and foreign currencies, net	76	(449)
Earned stock compensation	22,882	20,198
(Increase) decrease in deferred income taxes, net	(8,790)	10,164
Decrease (increase) in other assets	52,275	(32,765)
Decrease in accrued interest payable and other liabilities	(36,303)	(20,738)
Net cash provided by operating activities	463,820	358,172
Cash flows from investing activities:
Net increase in loans and leases	(446,880)	(567,291)
Proceeds from sales of loans and leases	646,587	293,808
Proceeds from maturities and paydowns of securities available-for-sale	231,474	329,876
Proceeds from sales of securities available-for-sale	500,101	185,533
Purchases of securities available-for-sale	(910,298)	(804,710)
Net (purchases) redemptions of Federal Home Loan Bank stock	(10,287)	4,620
Proceeds from sales of foreclosed assets	57	1,455
Purchases of premises and equipment, net	(9,250)	(5,892)
Proceeds from sales of premises and equipment	49	10,306
Proceeds from BOLI death benefit	1,901	2,478
Net decrease in equipment leased to others under operating leases	(6,000)	(17,956)
Net cash used in investing activities	(2,546)	(567,773)
Cash flows from financing activities:
Net (decrease) increase in noninterest-bearing deposits	(671,016)	255,874
Net (decrease) increase in interest-bearing deposits	(312,429)	649,776
Net increase (decrease) in borrowings	1,045,824	(655,413)
Early Repayment of Subordinated Debt	(12,372)	0
Common stock repurchased and restricted stock surrendered	(313,796)	(7,793)
Cash dividends paid	(214,136)	(182,495)
Net cash (used in) provided by financing activities	(477,925)	59,949
Net decrease in cash, cash equivalents, and restricted cash	(16,651)	(149,652)
Cash, cash equivalents, and restricted cash, beginning of period	398,437	419,670
Cash, cash equivalents, and restricted cash, end of period	381,786	270,018
Supplemental disclosures of cash flow information:
Cash paid for interest	78,884	48,402
Cash paid for income taxes	62,525	146,321
Loans transferred to foreclosed assets	3,235	580
Transfers from loans held for investment to loans held for sale	$ 0	$ 175,158