Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Operating Activities:
Net income	$ 198,385	$ 161,907
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan and lease losses	20,500	21,500
Deferred tax expense (benefit)	514	(4,247)
Depreciation and amortization	18,884	19,187
Amortization of premium/discount on earning assets and funding, net	22,785	26,625
Stock-based compensation	6,416	5,879
Gain on sale, net of write-down, on foreclosed and repossessed assets	(635)	(291)
Loss on sale, net of write-down, on premises and equipment	482	253
Increase in cash surrender value of life insurance policies	(7,234)	(7,215)
Gain from life insurance policies	(3,412)	(825)
Mortgage banking activities	(1,696)	(2,379)
Proceeds from sale of loans held for sale	63,464	90,063
Origination of loans held for sale	(74,076)	(86,694)
Net increase in right-of-use lease assets	(888)	0
Net (increase) decrease in derivative contract assets net of liabilities	(115,498)	65,421
Net increase in accrued interest receivable and other assets	(28,485)	(9,482)
Net decrease in accrued expenses and other liabilities	(1,545)	(23,176)
Net cash provided by operating activities	97,961	256,526
Investing Activities:
Purchases of available for sale investment securities	(255,885)	(455,042)
Proceeds from maturities and principal payments of available for sale investment securities	251,957	256,179
Purchases of held-to-maturity investment securities	(567,118)	(157,061)
Proceeds from maturities and principal payments of held-to-maturity investment securities	242,511	271,195
Net proceeds from Federal Home Loan Bank stock	30,915	10,273
Alternative investments capital call, net	(3,316)	(246)
Net increase in loans	(847,143)	(523,631)
Proceeds from loans not originated for sale	20,012	34
Proceeds from life insurance policies	2,270	2,429
Proceeds from the sale of foreclosed and repossessed assets	8,191	3,801
Additions to premises and equipment	(12,698)	(16,063)
Net cash used for investing activities (1)	(1,130,304)	(608,132)
Financing Activities:
Net increase in deposits	738,802	351,004
Proceeds from Federal Home Loan Bank advances	3,700,000	4,000,000
Repayments of Federal Home Loan Bank advances	(4,100,152)	(4,100,149)
Net decrease in securities sold under agreements to repurchase and other borrowings	375,046	219,299
Issuance of long-term debt	300,000	0
Debt issuance costs	(3,642)	0
Dividends paid to common shareholders	(67,165)	(53,974)
Dividends paid to preferred shareholders	(3,938)	(3,938)
Exercise of stock options	621	2,110
Common stock repurchase program	(13,003)	(12,158)
Common shares purchased related to stock compensation plan activity	(6,245)	(8,092)
Net cash (used for) provided by financing activities	920,324	394,102
Net decrease in cash and due from banks	(112,019)	42,496
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Beginning of Period	329,499	256,786
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents End of Period	217,480	299,282
Supplemental disclosure of cash flow information:
Interest paid	87,129	64,009
Income taxes paid	69,759	47,781
Noncash investing and financing activities:
Real Estate Owned, Transfer to Real Estate Owned	5,880	3,406
Transfer of loans from portfolio to loans-held-for-sale	15,438	35
Operating Lease, Right-of-Use Asset	158,270	0
Operating Lease, Liability	$ 178,724	$ 0