Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Assets [Abstract]
Cash and due from banks	$ 209,598	$ 164,757
Interest-earning deposits in financial institutions	431,033	148,469
Total cash and cash equivalents	640,631	313,226
Securities available-for-sale, at fair value	1,698,158	1,567,177
Federal Home Loan Bank stock, at cost	17,250	40,609
Total investment securities	1,715,408	1,607,786
Gross loans and leases	12,069,005	11,904,684
Deferred fees and costs	(34,816)	(22,252)
Allowance for loan and lease losses	(99,375)	(84,455)
Total loans and leases, net	11,934,814	11,797,977
Equipment leased to others under operating leases	117,182	122,506
Premises and equipment, net	35,984	36,551
Foreclosed assets, net	31,668	43,721
Goodwill	1,728,380	1,720,479
Core deposit and customer relationship intangibles, net	14,201	17,204
Deferred tax asset, net	211,556	284,411
Other assets	267,196	290,744
Total assets	16,697,020	16,234,605
Liabilities and Equity [Abstract]
Noninterest-bearing deposits	3,396,688	2,931,352
Interest-bearing deposits	9,185,128	8,823,776
Total deposits	12,581,816	11,755,128
Borrowings	2,751	383,402
Subordinated debentures	433,944	433,583
Accrued interest payable and other liabilities	127,019	156,262
Total liabilities	13,145,530	12,728,375
Commitments and Contingencies	0	0
Preferred stock ($0.01 par value; 5,000,000 shares authorized; none issued and outstanding)	0	0
Common stock	1,044	1,042
Additional paid-in capital	3,712,724	3,807,167
Accumulated deficit	(127,550)	(285,712)
Treasury stock, at cost (1,376,619 and 1,197,180 shares at June 30, 2015 and December 31, 2014)	(50,983)	(42,647)
Accumulated other comprehensive income, net	16,255	26,380
Total stockholders' equity	3,551,490	3,506,230
Total liabilities and stockholders' equity	$ 16,697,020	$ 16,234,605