Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Cash flows from operating activities
Net income	$ 140,584	$ 99,618
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses	15,828	10,279
Gains on sales of loans	(5,531)	(20,025)
Proceeds from sales of loans	392,570	391,475
Loans originated for sale	(379,584)	(353,034)
Net gains on sale of investment securities	(3)	(167)
Net losses (gains) from sales/writedowns of other real estate and repossessed assets	98	(871)
Depreciation of premises and equipment	8,384	8,989
Amortization of intangible assets	2,864	3,039
Additions to loan servicing rights	(4,251)	(4,137)
Valuation change in loan servicing rights	(2,272)	3,591
Net amortization of premiums and discounts on investment securities	9,123	8,880
Share-based compensation expense	4,078	6,928
Deferred income tax expense	4,473	30,937
Change in deferred tax valuation allowance	(72)	49
Net increase in interest receivable and other assets	(15,282)	(105,996)
Net (decrease) increase in interest payable and other liabilities	(5,671)	7,865
Net cash provided by operating activities	165,336	87,420
Debt securities – available-for-sale:
Proceeds from maturities, calls and principal reductions	157,185	143,335
Proceeds from sales and redemptions	4,215	10,050
Purchases	(775,497)	(685,689)
Investment securities – held-to-maturity:
Proceeds from maturities, calls and principal reductions	85,027	63,339
Purchases	(11,240)	(86,340)
Net increase in loans	(439,390)	(689,632)
Proceeds from sales of other real estate and repossessed assets	7,646	9,606
Purchases of premises and equipment, net of disposals	(7,458)	(10,437)
Proceeds from returns of investment in equity method investments	269	143
Net cash used in investing activities	(979,243)	(1,245,625)
Cash flows from financing activities
Net increase in interest- and noninterest-bearing demand deposits and savings accounts	247,254	354,480
Net increase (decrease) in time deposits	661,479	(23,235)
Net increase in collateralized customer deposits and other short-term borrowings	58,702	1,191,995
Repayment of long-term borrowings	(42,000)	(162,000)
Cash dividends paid	(40,137)	(38,539)
Proceeds from directors’ stock plans and exercise of stock options, net of shares withheld	2,558	1,639
Cash paid for payroll taxes upon conversion of share-based awards	(4,660)	(21,296)
Net cash provided by financing activities	883,196	1,303,044
Net increase in cash and cash equivalents	69,289	144,839
Cash and cash equivalents at beginning of period	455,991	474,402
Cash and cash equivalents at end of period	525,280	619,241
Supplemental disclosures of cash flow information:
Interest paid	56,575	30,287
Net income tax payments (refunds)	4,599	(4,689)
Non-cash activities:
Loans transferred to other real estate and repossessed assets	5,093	6,332
Net transfer of loans held-for-sale to loans held- for-investment	$ (2,171)	$ (1,957)