Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2016	Mar. 31, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Interest income:
Loans and leases	$ 224,326	$ 236,375	$ 203,781	$ 460,701	$ 405,878
Investment securities	22,420	22,547	14,570	44,967	26,765
Deposits in financial institutions	308	308	104	616	126
Total interest income	247,054	259,230	218,455	506,284	432,769
Interest expense:
Deposits	7,823	9,073	11,233	16,896	21,712
Borrowings	352	581	88	933	323
Subordinated debentures	5,122	4,982	4,582	10,104	9,107
Total interest expense	13,297	14,636	15,903	27,933	31,142
Net interest income	233,757	244,594	202,552	478,351	401,627
Provision for credit losses	13,903	20,140	6,529	34,043	22,963
Net interest income after provision for credit losses	219,854	224,454	196,023	444,308	378,664
Non-interest income:
Service charges on deposit accounts	3,633	3,856	2,612	7,489	5,186
Other commissions and fees	11,073	11,489	7,123	22,562	12,519
Leased equipment income	8,523	8,244	5,375	16,767	10,757
Gain on sale of loans and leases	388	245	163	633	163
Gain (loss) on sale of securities	478	8,110	(186)	8,588	3,089
FDIC loss sharing expense, net	(6,502)	(2,415)	(5,107)	(8,917)	(9,506)
Other income	4,528	5,010	9,643	9,538	18,286
Total noninterest income	22,121	34,539	19,623	56,660	40,494
Non-interest expense:
Compensation	62,174	61,065	49,033	123,239	96,770
Occupancy	12,193	12,632	10,588	24,825	21,188
Data processing	5,644	5,904	4,402	11,548	8,710
Other professional services	3,223	3,572	3,332	6,795	6,553
Insurance and assessments	4,951	4,965	4,716	9,916	7,741
Intangible asset amortization	4,371	4,746	1,502	9,117	3,003
Leased equipment depreciation	5,286	5,024	3,103	10,310	6,206
Foreclosed assets income, net	(3)	(561)	(2,340)	(564)	(2,004)
Acquisition, integration and reorganization costs	0	200	900	200	2,900
Other expense	12,242	13,141	10,040	25,383	18,569
Total noninterest expense	110,081	110,688	85,276	220,769	169,636
Earnings before income taxes	131,894	148,305	130,370	280,199	249,522
Income tax expense	(49,726)	(57,849)	(45,287)	(107,575)	(91,360)
Net earnings	$ 82,168	$ 90,456	$ 85,083	$ 172,624	$ 158,162
Earnings Per Share, Basic [Abstract]
Net earnings (usd per share)	$ 0.68	$ 0.74	$ 0.83	$ 1.42	$ 1.54
Earnings Per Share, Diluted [Abstract]
Net earnings (usd per share)	0.68	0.74	0.83	1.42	1.54
Dividends [Abstract]
Dividends declared per share (usd per share)	$ 0.50	$ 0.50	$ 0.5	$ 1.00	$ 1.00