CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Assets [Abstract]
Cash and noninterest-bearing due from banks	$ 181,088	$ 157,901
Restricted Cash, Current	243,313	137,045
Interest-bearing due from banks	598,084	210,784
Federal funds sold and other	1,883	20,977
Cash and cash equivalents	1,024,368	526,707
Available-for-sale Securities	3,030,564	3,539,995
Securities held-to-maturity, net of allowance for credit losses of $148,000 at March 31, 2020 (fair value of $1.1 billion)	1,059,257	188,996
Securities held-to-maturity (fair value of $201.2 million at Dec. 31, 2019)	1,059,405	188,996
Consumer loans held-for-sale	87,245	81,820
Commercial loans held-for-sale	6,850	17,585
Loans	20,396,853	19,787,876
Less allowance for credit losses	(222,465)	(94,777)
Loans, net	20,174,388	19,693,099
Premises and equipment, net	274,919	273,932
Equity method investment	285,671	278,037
Accrued interest receivable	82,198	84,462
Goodwill	1,819,811	1,819,811
Core deposits and other intangible assets	48,610	51,130
Other real estate owned	27,182	29,487
Other assets	1,343,117	1,220,435
Total assets	29,264,180	27,805,496
Deposits:
Noninterest-bearing	4,963,415	4,795,476
Interest-bearing	4,025,382	3,630,168
Savings and money market accounts	8,144,409	7,813,939
Time	4,199,965	3,941,445
Total deposits	21,333,171	20,181,028
Securities sold under agreements to repurchase	186,548	126,354
Federal Home Loan Bank advances	2,317,520	2,062,534
Subordinated debt and other borrowings	669,658	749,080
Accrued interest payable	33,931	42,183
Other liabilities	338,224	288,569
Total liabilities	24,879,052	23,449,748
Stockholders' equity:
Preferred stock, no par value; 10.0 million shares authorized; no shares issued and outstanding	0	0
Common stock, par value $1.00; 180.0 million shares authorized; 75.8 million and 76.5 million shares issued and outstanding at March 31, 2020 and Dec. 31, 2019, respectively	75,800	76,564
Additional paid-in capital	3,015,521	3,064,467
Retained earnings	1,168,301	1,184,183
Accumulated other comprehensive income, net of taxes	125,506	30,534
Total stockholders' equity	4,385,128	4,355,748
Total liabilities and stockholders' equity	$ 29,264,180	$ 27,805,496