Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating activities:
Net income	$ 147,918	$ 134,743	$ 50,244
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan and lease losses	25,560	13,170	10,964
Depreciation of premises and equipment, net	15,852	8,329	8,557
(Accretion) amortization of fees, premiums and discounts, net	(45,548)	15,255	19,082
Amortization of intangible assets	11,113	2,942	3,078
Amortization of right of use lease asset	22,850
Accretion of the discounted lease liability	(12,507)		0
Debt extinguishment cost	0	0	695
Stock-based compensation expense	3,608	2,292	3,396
Unrealized gains on equity investments	(26,175)	(20,745)	0
Deferred income tax expense	7,074	3,378	17,899
(Recovery of) provision for legal settlement	0	0	12,000
Increase in value of bank-owned life insurance	(806)	(158)	(1,130)
Increase in capitalized interest, net	(3,390)	(3,601)	(4,228)
Decrease (increase) in accrued interest receivable	1,406	(2,596)	(2,378)
Increase in other assets	(4,676)	(6,297)	(2,517)
Origination of loans held-for-sale	(479,289)	(351,108)	(354,659)
Proceeds from sales of loans held-for-sale	406,012	352,002	369,986
Gain on mortgage banking activities, net	(11,053)	(6,286)	(6,293)
Gain on sale of securities, net	(333)	(21)	(1,984)
Realized gains on sale of equity investment	0	(3,757)	0
Increase (decrease) in accrued interest payable	1,203	863	(114)
Increase (decrease) in other liabilities	30,922	(2,931)	7,353
Loss on sale of other real estate owned and valuation adjustments, net	125	100	217
Net cash provided by operating activities	89,866	135,574	130,168
Investing activities:
Repayments, maturities and calls of investment securities held to maturity	16,170	9,245	1,230
Sale of investment securities available-for-sale	618,194	7,012	457,046
Purchases of investment securities available-for-sale	(958,259)	(498,465)	(696,581)
Repayments of investment securities available-for-sale	269,697	112,665	197,765
Proceeds from BOLI surrender/death benefit	59,710	96,429	371
Net cash for business combinations	76,072	0	0
Net decrease (increase) in loans	201,934	(101,174)	(343,858)
Purchases of Visa Class B shares	0	(1,568)	(10,072)
Sale of Visa Class B shares	0	6,186	0
Purchases of FHLB stock	(394,428)	(169,613)	(160,089)
Redemption of FHLB stock	415,771	181,638	167,053
Sales of assets acquired through foreclosure, net	3,089	3,037	6,077
Sale of premise and equipment	71	198	0
Investment in premises and equipment, net	(14,198)	(5,500)	(7,728)
Net cash provided by (used for) investing activities	293,823	(359,910)	(388,786)
Financing activities:
Net increase in demand and saving deposits	69,761	393,827	353,521
(Decrease) increase in time deposits	(55,400)	43,871	35,887
(Decrease) increase in brokered deposits	(156,396)	(31,712)	90,482
Decrease in loan payable	0	0	(338)
Receipts from FHLB advances	32,320,456	83,721,532	143,852,751
Repayments of FHLB advances	(32,536,246)	(84,103,068)	(143,996,986)
Receipts from federal funds purchased	32,252,775	21,239,675	23,008,000
Repayments of federal funds purchased	(32,215,750)	(21,109,700)	(23,110,000)
Dividends paid	(22,463)	(13,249)	(9,425)
Issuance of common stock and exercise of common stock options	7,755	11,253	3,421
Redemption of senior debt	0	0	(55,000)
Purchase of treasury stock	(97,186)	(31,202)	(11,752)
Net cash (used for) provided by financing activities	(432,694)	121,227	160,561
(Decrease) increase in cash and cash equivalents	(49,005)	(103,109)	(98,057)
Cash and cash equivalents at beginning of period	620,757	723,866	821,923
Cash and cash equivalents at end of period	571,752	620,757	723,866
Supplemental Disclosure of Cash Flow Information:
Cash paid for interest during the period	74,942	45,636	33,569
Income Taxes Paid, Net	33,843	33,316	31,441
Non-cash information:
Loans transferred to other real estate owned	2,541	3,302	5,206
Loans transferred to portfolio from held-for-sale at fair value	24,862	9,553	13,142
Fair value of assets acquired, net of cash received	5,032,156	0	0
Fair value of liabilities assumed	5,108,228	0	0
Non-cash goodwill adjustments, net	0	$ 0	$ (1,532)
Right of use asset	121,288
Lease liability	$ 132,346