Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Operating activities
Net income	$ 45,110	$ 33,826
Adjustments to reconcile net income to net cash provided (used in) by operating activities:
Provision for loan losses	1,500	1,750
Depreciation, amortization and accretion	409	650
Deferred income tax expense	5,949	1,990
Funding of mortgage loans held for sale	(384,103)	(362,803)
Proceeds from sales of mortgage loans held for sale	416,032	275,445
Gains on sales of mortgage loans held for sale	(7,888)	(8,798)
Gains on sales of securities	(13)	0
(Gains) losses on sales of premises and equipment	(89)	8
Stock-based compensation expense	2,637	1,858
Payments on and proceeds from sales of other loans held for sale	70,375	0
Decrease in other assets	5,982	9,623
Increase in other liabilities	(15,794)	(14,720)
Net cash provided by (used in) operating activities	140,107	(61,171)
Investing activities
Purchases of securities available for sale	(49,577)	(317,922)
Proceeds from sales of securities available for sale	10,611	0
Proceeds from call/maturities of securities available for sale	48,509	29,335
Net increase in loans	(808)	(74,344)
Purchases of premises and equipment	(7,242)	(4,384)
Proceeds from sales of premises and equipment	135	0
Proceeds from sales of FHLB stock	10,441	0
Proceeds from sales of other assets	12,965	2,085
Other, net	(104)	0
Net cash provided by (used in) investing activities	24,930	(365,230)
Financing activities
Net increase in noninterest-bearing deposits	47,517	20,712
Net increase in interest-bearing deposits	93,175	416,759
Net decrease in short-term borrowings	(300,116)	(32,061)
Repayment of long-term debt	(216)	(230)
Cash paid for dividends	(12,442)	(9,455)
Net stock-based compensation transactions	0	201
Net cash (used in) provided by financing activities	(172,082)	395,926
Net decrease in cash and cash equivalents	(7,045)	(30,475)
Cash and cash equivalents at beginning of period	569,111	281,453
Cash and cash equivalents at end of period	562,066	250,978
Supplemental disclosures
Cash paid for interest	23,887	12,656
Cash paid for income taxes	5,325	6,280
Noncash transactions:
Transfers of loans to other real estate owned	885	1,154
Financed sales of other real estate owned	120	418
Transfers of loans held for sale to loans held for investment	0	$ 442
Recognition of operating right-of-use assets	54,338
Recognition of operating lease liabilities	$ 57,857