Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Operating activities:
Net income	$ 153,370	$ 157,402
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for probable loan losses	15,363	3,212
Specific reserve, other real estate owned	154	3,033
Depreciation of bank premises and equipment	21,140	19,097
Gain on sale of bank premises and equipment	(207)	(293)
Gain on sale of other real estate owned	(1,246)	(1,317)
Accretion of investment securities discounts	(311)	(209)
Amortization of investment securities premiums	13,678	15,620
Investment securities transactions, net	12	141
Unrealized loss on equity securities with readily determinable fair values	(235)	312
Stock based compensation expense	744	755
Earnings from affiliates and other investments	(2,869)	(12,247)
Deferred tax expense	330	1,373
Decrease in accrued interest receivable	1,444	65
Increase in other assets	(17,430)	(48,747)
Net increase in other liabilities	27,250	40,533
Net cash provided by operating activities	211,187	178,730
Investing activities:
Proceeds from maturities of securities		1,075
Proceeds from sales and calls of available for sale securities	92,980	37,675
Proceeds from sales of equity securities with readily determinable fair values		21,607
Purchases of available for sale securities	(380,095)	(47,346)
Principal collected on mortgage backed securities	566,455	529,956
Net increase in loans	(372,121)	(168,823)
Purchases of other investments	(33,940)	(34,914)
Distributions from other investments	52,693	2,894
Purchases of bank premises and equipment	(23,809)	(16,256)
Proceeds from sales of bank premises and equipment	3,685	3,633
Proceeds from sales of other real estate owned	1,830	1,413
Net cash (used in) provided by investing activities	(92,322)	330,914
Financing activities:
Net increase in non-interest bearing demand deposits	121,090	188,518
Net decrease in savings and interest bearing demand deposits	(13,475)	(13,938)
Net increase (decrease) in time deposits	7,901	(73,871)
Net increase (decrease) in securities sold under repurchase agreements	59,345	(20,002)
Net decrease in other borrowed funds	(249,109)	(520,325)
Redemption of long-term debt	(25,774)
Repurchase of outstanding common stock warrant		(29,005)
Purchase of treasury stock	(17,817)	(57)
Proceeds from stock transactions	1,517	1,158
Payments of cash dividends - common	(32,821)	(21,815)
Net cash used in financing activities	(149,143)	(489,337)
(Decrease) increase in cash and cash equivalents	(30,278)	20,307
Cash and cash equivalents at beginning of period	316,797	265,357
Cash and cash equivalents at end of period	286,519	285,664
Supplemental cash flow information:
Interest paid	43,262	37,051
Income taxes paid	38,591	39,715
Non-cash investing and financing activities:
Net transfers from loans to other real estate owned	21,381	31,609
Dividends declared, not yet paid on common stock	35,848	$ 27,784
Establishment of lease liability and right-of-use asset	$ 6,171