Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014
Interest income:
Loans and leases	$ 202,097	$ 197,472	$ 77,463
Investment securities	12,195	12,205	10,823
Deposits in financial institutions	22	19	74
Total interest income	214,314	209,696	88,360
Interest expense:
Deposits	10,479	9,972	1,225
Borrowings	235	144	79
Subordinated debentures	4,525	4,597	1,041
Total interest expense	15,239	14,713	2,345
Net interest income	199,075	194,983	86,015
Provision (negative provision) for credit losses	16,434	2,063	(644)
Net interest income after provision (negative provision) for credit losses	182,641	192,920	86,659
Non-interest income:
Service charges on deposit accounts	2,574	2,787	3,002
Other commissions and fees	5,396	4,556	1,932
Leased equipment income	5,382	5,382	0
Gain on sale of loans and leases	0	7	106
Gain on securities	3,275	0	4,752
FDIC loss sharing expense, net	(4,399)	(4,360)	(11,430)
Other income	8,643	4,331	6,329
Total noninterest income	20,871	12,703	4,691
Non-interest expense:
Compensation	47,737	45,930	28,627
Occupancy	10,600	10,745	7,595
Data processing	4,308	4,050	2,540
Other professional services	3,221	3,181	1,523
Insurance and assessments	3,025	3,115	1,593
Intangible asset amortization	1,501	1,619	1,364
Leased equipment depreciation	3,103	3,103	0
Foreclosed assets expense (income), net	336	1,938	(1,861)
Acquisition, integration and reorganization costs	2,000	7,381	2,200
Other expense	8,529	10,243	6,583
Total noninterest expense	84,360	91,305	50,164
Earnings from continuing operations before taxes	119,152	114,318	41,186
Income tax expense	(46,073)	(43,261)	(15,281)
Net earnings from continuing operations	73,079	71,057	25,905
Loss from discontinued operations before taxes	0	(105)	(1,413)
Income tax benefit	0	47	588
Net loss from discontinued operations	0	(58)	(825)
Net earnings	$ 73,079	$ 70,999	$ 25,080
Earnings Per Share, Basic [Abstract]
Net earnings from continuing operations	$ 0.71	$ 0.69	$ 0.57
Net earnings	$ 0.71	$ 0.69	$ 0.55
Earnings Per Share, Diluted [Abstract]
Net earnings from continuing operations	$ 0.71	$ 0.69	$ 0.57
Net earnings	$ 0.71	$ 0.69	$ 0.55
Dividends [Abstract]
Dividends declared per share	$ 0.50	$ 0.50	$ 0.25