Condensed Consolidated Statements of Earnings - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Interest expense:
Deposits	$ 38,720	$ 34,235	$ 16,367	$ 72,955	$ 30,185
Borrowings	7,210	7,710	2,649	14,920	3,569
Subordinated debentures	7,705	7,738	7,166	15,443	13,703
Total interest expense	53,635	49,683	26,182	103,318	47,457
Loans and leases	284,236	274,229	260,300	558,465	511,385
Investment securities	28,948	29,680	27,730	58,628	53,868
Deposits in financial institutions	1,349	650	484	1,999	1,036
Total interest income	314,533	304,559	288,514	619,092	566,289
Net interest income	260,898	254,876	262,332	515,774	518,832
Provision for credit losses	8,000	4,000	17,500	12,000	21,500
Net interest income after provision for credit losses	252,898	250,876	244,832	503,774	497,332
Noninterest income:
Other commissions and fees	11,590	11,008	11,767	22,598	22,032
Leased equipment income	9,182	9,282	9,790	18,464	19,377
Service charges on deposit accounts	3,771	3,730	4,265	7,501	8,439
Gain on sale of loans and leases	326	0	106	326	4,675
Gain on sale of securities	22,192	2,161	253	24,353	6,564
Other income	3,832	4,883	13,457	8,715	17,110
Total noninterest income	50,893	31,064	39,638	81,957	78,197
Noninterest expense:
Compensation	68,956	70,845	69,913	139,801	140,936
Occupancy	14,457	14,320	13,575	28,777	26,798
Data processing	6,817	6,925	6,896	13,742	13,555
Leased equipment depreciation	5,558	5,651	5,237	11,209	10,612
Intangible asset amortization	4,870	4,870	5,587	9,740	11,933
Other professional services	4,629	4,513	5,257	9,142	9,696
Insurance and assessments	4,098	4,038	5,330	8,136	11,057
Loan expense	3,451	2,885	3,058	6,336	5,329
Acquisition, integration and reorganization costs	0	618	0	618	0
Foreclosed assets (income) expense, net	(146)	29	(61)	(117)	(183)
Other expense	12,737	11,593	11,657	24,330	24,111
Total noninterest expense	125,427	126,287	126,449	251,714	253,844
Earnings before income taxes	178,364	155,653	158,021	334,017	321,685
Income tax expense	(50,239)	(43,049)	(42,286)	(93,288)	(87,674)
Net earnings	$ 128,125	$ 112,604	$ 115,735	$ 240,729	$ 234,011
Earnings per share:
Net earnings (usd per share)	$ 1.07	$ 0.92	$ 0.92	$ 1.99	$ 1.85
Net earnings (usd per share)	$ 1.07	$ 0.92	$ 0.92	$ 1.99	$ 1.85