Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Assets [Abstract]
Cash and due from banks	$ 286,371	$ 161,020
Interest-earning deposits in financial institutions	253,994	235,466
Total cash and cash equivalents	540,365	396,486
Securities available-for-sale, at fair value	3,341,335	3,559,437
Federal Home Loan Bank stock, at cost	19,386	19,710
Total investment securities	3,360,721	3,579,147
Gross loans and leases	14,806,427	14,528,165
Deferred fees, net	(63,581)	(49,911)
Allowance for loan and lease losses	147,976	115,111
Total loans and leases, net	14,594,870	14,363,143
Equipment leased to others under operating leases	198,931	197,452
Premises and equipment, net	38,977	39,197
Foreclosed assets, net	15,113	22,120
Goodwill	2,173,949	2,176,291
Core deposit and customer relationship intangibles, net	39,542	53,220
Deferred tax asset, net	27,073	126,389
Other assets	325,750	335,045
Total assets	21,315,291	21,288,490
Liabilities and Equity [Abstract]
Noninterest-bearing deposits	6,521,946	6,171,455
Interest-bearing deposits	9,123,722	9,494,727
Total deposits	15,645,668	15,666,182
Borrowings	541,011	621,914
Subordinated debentures	441,112	436,000
Accrued interest payable and other liabilities	144,905	166,703
Total liabilities	16,772,696	16,890,799
Commitments and contingencies (Note 8)
Preferred stock ($0.01 par value; 5,000,000 shares authorized; none issued and outstanding)	0	0
Common stock ($0.01 par value, 200,000,000 shares authorized at September 30, 2016 and December 31, 2015; 123,320,121 and 122,791,729 shares issued, respectively, including 1,407,486 and 1,211,951 shares of unvested restricted stock, respectively)	1,233	1,228
Additional paid-in capital	4,244,521	4,405,775
Retained earnings	280,426	13,907
Treasury stock, at cost (1,502,597 and 1,378,002 shares at September 30, 2016 and December 31, 2015)	(55,658)	(51,047)
Accumulated other comprehensive income, net	72,073	27,828
Total stockholders' equity	4,542,595	4,397,691
Total liabilities and stockholders' equity	$ 21,315,291	$ 21,288,490