Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
CASH FLOWS FROM OPERATING ACTIVITIES:
Net earnings	$ 80,345	$ 72,152
Adjustments to reconcile net earnings to net cash provided by operating activities:
Depreciation and amortization	5,946	6,433
Provision for loan losses	1,565	2,415
Securities premium amortization (discount accretion), net	12,217	14,109
Gain (loss) on sale of assets, net	824	(1,245)
Deferred federal income tax expense (benefit)	2,206	(908)
Change in loans held-for-sale	(631)	(9,009)
Change in other assets	1,021	(1,192)
Change in other liabilities	5,219	6,218
Total adjustments	28,367	16,821
Net cash provided by operating activities	108,712	88,973
CASH FLOWS FROM INVESTING ACTIVITIES:
Cash received in acquisition of Commercial Bancshares, Inc.		18,653
Net decrease in interest-bearing time deposits in banks	498
Activity in available-for-sale securities:
Sales	66,052	149,125
Maturities	2,201,877	3,208,139
Purchases	(2,280,686)	(3,471,387)
Net increase in loans	(88,629)	(80,480)
Purchases of bank premises and equipment and other assets	(6,360)	(8,544)
Proceeds from sale of bank premises and equipment and other assets	187	776
Net cash used in investing activities	(107,061)	(183,718)
CASH FLOWS FROM FINANCING ACTIVITIES:
Net increase (decrease) in noninterest-bearing deposits	51,445	(97,737)
Net increase in interest-bearing deposits	137,932	3,481
Net increase (decrease) in borrowings	(106,701)	125,935
Common stock transactions:
Proceeds from stock issuances	3,186	2,319
Dividends paid	(28,463)	(25,434)
Net cash provided by financing activities	57,399	8,564
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	59,050	(86,181)
CASH AND CASH EQUIVALENTS, beginning of period	248,647	372,347
CASH AND CASH EQUIVALENTS, end of period	307,697	286,166
SUPPLEMENTAL INFORMATION AND NONCASH TRANSACTIONS:
Interest paid	15,062	8,074
Federal income taxes paid	12,752	12,762
Transfer of loans and bank premises to other real estate	364	126
Investment securities purchased but not settled	29,355
Restricted Stock Grant to Officers and Directors	$ 1,426	523
Stocks issued in acquisition of Commercial Bancshares, Inc.		$ 58,087