Condensed Consolidated Statements of Earnings - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2017	Mar. 31, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Interest income:
Loans and leases	$ 234,618	$ 224,178	$ 224,326	$ 458,796	$ 460,701
Investment securities	24,689	23,039	22,420	47,728	44,967
Deposits in financial institutions	237	192	308	429	616
Total interest income	259,544	247,409	247,054	506,953	506,284
Interest expense:
Deposits	10,205	8,377	7,823	18,582	16,896
Borrowings	1,066	1,018	352	2,084	933
Subordinated debentures	5,800	5,562	5,122	11,362	10,104
Total interest expense	17,071	14,957	13,297	32,028	27,933
Net interest income	242,473	232,452	233,757	474,925	478,351
Provision for credit losses	11,499	24,728	13,903	36,227	34,043
Net interest income after provision for credit losses	230,974	207,724	219,854	438,698	444,308
Noninterest income:
Service charges on deposit accounts	3,510	3,758	3,633	7,268	7,489
Other commissions and fees	10,583	10,390	11,073	20,973	22,562
Leased equipment income	11,635	9,475	8,523	21,110	16,767
Gain on sale of loans and leases	649	712	388	1,361	633
Gain (loss) on sale of securities	1,651	(99)	478	1,552	8,588
FDIC loss sharing expense, net	0	0	(6,502)	0	(8,917)
Other income	7,254	10,878	4,528	18,132	9,538
Total noninterest income	35,282	35,114	22,121	70,396	56,660
Noninterest expense:
Compensation	65,288	64,880	62,174	130,168	123,239
Occupancy	11,811	11,608	12,193	23,419	24,825
Data processing	6,337	7,015	5,644	13,352	11,548
Other professional services	3,976	3,378	3,401	7,354	6,973
Insurance and assessments	4,856	4,791	4,951	9,647	9,916
Intangible asset amortization	3,065	3,064	4,371	6,129	9,117
Leased equipment depreciation	5,232	5,625	5,286	10,857	10,310
Foreclosed assets (income) expense, net	(157)	143	(3)	(14)	(564)
Acquisition, integration and reorganization costs	1,700	500	0	2,200	200
Loan expense	3,884	3,387	2,145	7,271	4,300
Other expense	11,715	12,153	9,919	23,868	20,905
Total noninterest expense	117,707	116,544	110,081	234,251	220,769
Earnings before income taxes	148,549	126,294	131,894	274,843	280,199
Income tax expense	(54,902)	(47,626)	(49,726)	(102,528)	(107,575)
Net earnings	$ 93,647	$ 78,668	$ 82,168	$ 172,315	$ 172,624
Earnings per share:
Net earnings (usd per share)	$ 0.77	$ 0.65	$ 0.68	$ 1.42	$ 1.42
Net earnings (usd per share)	0.77	0.65	0.68	1.42	1.42
Dividends declared per share (usd per share)	$ 0.50	$ 0.50	$ 0.50	$ 1.00	$ 1.00