CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating activities:
Net income	$ 400,881	$ 359,440	$ 173,979
Adjustments to reconcile net income to net cash provided by operating activities:
Net amortization/accretion of premium/discount on securities	20,294	19,141	12,847
Depreciation, amortization and accretion	8,342	(23,604)	(23,618)
Provision for loan losses	27,283	34,377	23,664
Gains on mortgage loans sold, net	(24,335)	(14,564)	(18,625)
Investment losses (gains) on sales, net	5,941	2,254	8,265
Stock-based compensation expense	21,226	17,636	19,538
Deferred tax expense	14,696	11,765	28,165
Revaluation of deferred tax assets and liabilities	0	0	31,486
Losses (gains) on disposition of other real estate and other investments	2,927	84	(203)
Income from equity method investment	(90,111)	(51,222)	(37,958)
Dividends received from equity method investment	51,312	33,651	21,650
Excess tax benefit from stock compensation	(1,011)	(2,966)	(5,366)
Gains on other loans sold, net	3,624	3,287	1,488
Commercial loans held for sale originated	(402,623)	(356,597)	(177,434)
Commercial loans held for sale sold	404,615	369,387	176,062
Consumer loans held for sale originated	(1,396,968)	(1,195,435)	(1,100,866)
Consumer loans held for sale sold	1,373,678	1,234,551	1,090,489
Increase in other assets	(57,499)	(24,471)	(37,023)
Increase (decrease) in other liabilities	79,264	60,617	(17,700)
Net cash provided by operating activities	434,288	470,757	165,864
Activities in securities available-for-sale:
Purchases	(1,455,073)	(1,314,721)	(1,290,717)
Sales	737,717	169,850	363,898
Maturities, prepayments and calls	372,300	323,571	323,235
Activities in securities held-to-maturity:
Purchases	(3,822)	0	0
Maturities, prepayments and calls	8,300	5,775	4,115
Increase in loans, net	(1,927,811)	(1,995,424)	(1,558,646)
Purchases of premises and equipment and software	(42,153)	(23,739)	(53,499)
Purchase of BOLI	(110,000)	(100,000)	(55,000)
Proceeds from BOLI settlement	321	3,467	0
Proceeds from sales of software, premises, and equipment	66	2,967	23
Acquisitions, net of cash acquired	44,594	0	155,142
Proceeds from Sale of Other Real Estate	8,446	16,088	3,725
Payments related to derivative instruments	106,832	0	0
Increase in other investments	(55,926)	(56,918)	(7,804)
Net cash used in investing activities	(2,619,061)	(2,969,084)	(2,115,528)
Financing activities:
Net increase in deposits	1,332,491	2,399,407	1,488,274
Net increase (decrease) in repurchase agreements	21,613	(30,521)	(12,754)
Advances from Federal Home Loan Bank: Issuances	2,672,500	1,664,906	1,964,750
Advances from Federal Home Loan Bank: Payments	(2,053,555)	(1,541,212)	(1,051,067)
Proceeds from subordinated debt and other borrowings, net of issuance costs	316,078	19,850	0
Repayments of other borrowings	184,175	620	220
Principal payments of capital lease obligation	(226)	(168)	(149)
Proceeds from common stock issuance	0	0	192,194
Exercise of common stock options and stock appreciation rights, net of shares surrendered for taxes	(3,694)	(5,071)	494
Repurchase of common stock	(61,416)	(20,694)	0
Common stock dividends paid	(49,828)	(45,454)	(35,907)
Net cash provided by financing activities	1,989,788	2,440,423	2,545,615
Net increase (decrease) in cash, cash equivalents, and restricted cash	(194,985)	(57,904)	595,951
Cash, cash equivalents, and restricted cash, beginning of year	721,692	779,596	183,645
Cash, cash equivalents, and restricted cash, end of year	$ 526,707	$ 721,692	$ 779,596