Consolidated Statements of Cash Flows (Unaudited) - USD ($)	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Operating activities
Net income	$ 91,735,000	$ 70,536,000
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Provision for loan losses	2,400,000	3,560,000
Depreciation, amortization and accretion	1,607,000	1,854,000
Deferred income tax expense	8,585,000	3,476,000
Funding of mortgage loans held for sale	(938,825,000)	(838,564,000)
Proceeds from sales of mortgage loans held for sale	856,243,000	721,351,000
Gains on sales of mortgage loans held for sale	(20,789,000)	(19,517,000)
Gains on sales of securities	(5,000)	0
Gains on sales of premises and equipment	(1,073,000)	(225,000)
Stock-based compensation expense	4,719,000	3,712,000
Net change in other loans held for sale	55,792,000	0
Increase in other assets	(4,815,000)	(6,649,000)
Decrease in other liabilities	(10,762,000)	(12,657,000)
Net cash provided by (used in) operating activities	44,812,000	(73,123,000)
Investing activities
Purchases of securities available for sale	(125,503,000)	(497,845,000)
Proceeds from sales of securities available for sale	12,612,000	0
Proceeds from call/maturities of securities available for sale	120,738,000	63,655,000
Net decrease (increase) in loans	37,634,000	(140,205,000)
Purchases of premises and equipment	(16,491,000)	(10,313,000)
Proceeds from sales of premises and equipment	2,240,000	233,000
Net change in FHLB stock	8,710,000	0
Proceeds from sales of other assets	15,295,000	4,026,000
Other, net	2,000	0
Net cash provided by (used in) investing activities	55,237,000	(580,449,000)
Financing activities
Net increase in noninterest-bearing deposits	90,278,000	48,137,000
Net (decrease) increase in interest-bearing deposits	(28,100,000)	413,003,000
Net (decrease) increase in short-term borrowings	(248,695,000)	223,579,000
Repayment of long-term debt	(430,000)	(436,000)
Cash paid for dividends	(25,413,000)	(19,415,000)
Repurchase of shares in connection with stock repurchase program	(12,938,000)	0
Net stock-based compensation transactions	0	203,000
Net cash (used in) provided by financing activities	(225,298,000)	665,071,000
Net (decrease) increase in cash and cash equivalents	(125,249,000)	11,499,000
Cash and cash equivalents at beginning of period	569,111,000	281,453,000
Cash and cash equivalents at end of period	443,862,000	292,952,000
Supplemental disclosures
Cash paid for interest	47,599,000	24,652,000
Cash paid for income taxes	13,820,000	12,044,000
Noncash transactions:
Transfers of loans to other real estate owned	1,796,000	2,291,000
Financed sales of other real estate owned	254,000	418,000
Transfers of loans held for sale to loans held for investment	189,000	$ 663,000
Recognition of operating right-of-use assets	75,042,000
Recognition of operating lease liabilities	$ 78,561,000