Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Interest income:
Loans and leases	$ 225,370	$ 224,326	$ 193,539	$ 686,071	$ 599,417
Investment securities	22,187	22,420	13,955	67,154	40,720
Deposits in financial institutions	298	308	178	914	304
Total interest income	247,855	247,054	207,672	754,139	640,441
Interest expense:
Deposits	7,247	7,823	10,400	24,143	32,112
Borrowings	695	352	72	1,628	395
Subordinated debentures	5,278	5,122	4,680	15,382	13,787
Total interest expense	13,220	13,297	15,152	41,153	46,294
Net interest income	234,635	233,757	192,520	712,986	594,147
Provision for credit losses	8,471	13,903	8,746	42,514	31,709
Net interest income after provision for credit losses	226,164	219,854	183,774	670,472	562,438
Non-interest income:
Service charges on deposit accounts	3,488	3,633	2,601	10,977	7,787
Other commissions and fees	12,528	11,073	6,376	35,090	18,895
Leased equipment income	8,538	8,523	5,475	25,305	16,232
Gain on sale of loans and leases	157	388	27	790	190
Gain on sale of securities	382	478	655	8,970	3,744
FDIC loss sharing expense, net	0	(6,502)	(4,449)	(8,917)	(13,955)
Other income	1,827	4,528	5,073	11,365	23,359
Total noninterest income	26,920	22,121	15,758	83,580	56,252
Non-interest expense:
Compensation	62,661	62,174	48,152	185,900	144,922
Occupancy	12,010	12,193	10,762	36,835	31,950
Data processing	6,234	5,644	4,322	17,782	13,032
Other professional services	4,625	3,401	3,396	11,598	9,949
Insurance and assessments	4,324	4,951	3,805	14,240	11,546
Intangible asset amortization	4,224	4,371	1,497	13,341	4,500
Leased equipment depreciation	5,298	5,286	3,162	15,608	9,368
Foreclosed assets (income) expense, net	(248)	(3)	4,521	(812)	2,517
Acquisition, integration and reorganization costs	0	0	747	200	3,647
Other expense	11,582	12,064	9,775	36,787	28,344
Total noninterest expense	110,710	110,081	90,139	331,479	259,775
Earnings before income taxes	142,374	131,894	109,393	422,573	358,915
Income tax expense	(48,479)	(49,726)	(39,777)	(156,054)	(131,137)
Net earnings	$ 93,895	$ 82,168	$ 69,616	$ 266,519	$ 227,778
Earnings Per Share, Basic [Abstract]
Net earnings (usd per share)	$ 0.77	$ 0.68	$ 0.68	$ 2.19	$ 2.21
Earnings Per Share, Diluted [Abstract]
Net earnings (usd per share)	0.77	0.68	0.68	2.19	2.21
Dividends [Abstract]
Dividends declared per share (usd per share)	$ 0.50	$ 0.50	$ 0.5	$ 1.50	$ 1.5