Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015
Interest income:
Loans and leases	$ 236,375	$ 219,677	$ 202,097
Investment securities	22,547	23,648	12,195
Deposits in financial institutions	308	172	22
Total interest income	259,230	243,497	214,314
Interest expense:
Deposits	9,073	9,391	10,479
Borrowings	581	159	235
Subordinated debentures	4,982	4,748	4,525
Total interest expense	14,636	14,298	15,239
Net interest income	244,594	229,199	199,075
Provision for credit losses	20,140	13,772	16,434
Net interest income after provision for credit losses	224,454	215,427	182,641
Non-interest income:
Service charges on deposit accounts	3,856	3,901	2,574
Other commissions and fees	11,489	12,691	5,396
Leased equipment income	8,244	7,791	5,382
Gain on sale of loans and leases	245	183	0
Gain on sale of securities	8,110	0	3,275
FDIC loss sharing expense, net	(2,415)	(4,291)	(4,399)
Other income	5,010	7,783	8,643
Total noninterest income	34,539	28,058	20,871
Non-interest expense:
Compensation	61,065	58,992	47,737
Occupancy	12,632	12,194	10,600
Data processing	5,904	5,585	4,308
Other professional services	3,572	3,811	3,221
Insurance and assessments	4,965	5,450	3,025
Intangible asset amortization	4,746	4,910	1,501
Leased equipment depreciation	5,024	4,235	3,103
Foreclosed Real Estate (Income) Expense	(561)	(3,185)	336
Acquisition, integration and reorganization costs	200	17,600	2,000
Other expense	13,141	12,672	8,529
Total noninterest expense	110,688	122,264	84,360
Earnings before income taxes	148,305	121,221	119,152
Income tax expense	(57,849)	(49,380)	(46,073)
Net earnings	$ 90,456	$ 71,841	$ 73,079
Earnings Per Share, Basic [Abstract]
Net earnings (usd per share)	$ 0.74	$ 0.60	$ 0.71
Earnings Per Share, Diluted [Abstract]
Net earnings (usd per share)	0.74	0.60	0.71
Dividends [Abstract]
Dividends declared per share (usd per share)	$ 0.50	$ 0.50	$ 0.5