Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Operating activities
Net income	$ 33,826	$ 23,972
Adjustments to reconcile net income to net cash (used in) provided by operating activities:
Provision for loan losses	1,750	1,500
Depreciation, amortization and accretion	650	358
Deferred income tax expense	1,990	3,946
Funding of mortgage loans held for sale	(362,803)	(318,144)
Proceeds from sales of mortgage loans held for sale	275,445	343,945
Gains on sales of mortgage loans held for sale	(8,798)	(6,554)
Penalty on prepayment of debt	0	205
Losses on sales of premises and equipment	8	512
Stock-based compensation expense	1,858	1,174
Decrease in other assets	9,623	18,882
Decrease in other liabilities	(14,720)	(14,662)
Net cash (used in) provided by operating activities	(61,171)	55,134
Investing activities
Purchases of securities available for sale	(317,922)	(52,683)
Proceeds from sales of securities available for sale	0	2,946
Proceeds from call/maturities of securities available for sale	29,335	30,800
Proceeds from call/maturities of securities held to maturity	0	7,710
Net increase in loans	(74,344)	(31,974)
Purchases of premises and equipment	(4,384)	(4,441)
Proceeds from sales of premises and equipment	0	13
Proceeds from sales of other assets	2,085	5,307
Net cash used in investing activities	(365,230)	(42,322)
Financing activities
Net increase in noninterest-bearing deposits	20,712	18,224
Net increase in interest-bearing deposits	416,759	154,001
Net decrease in short-term borrowings	(32,061)	(99,721)
Repayment of long-term debt	(230)	(10,790)
Cash paid for dividends	(9,455)	(8,030)
Net stock-based compensation transactions	201	(1,976)
Net cash provided by financing activities	395,926	51,708
Net (decrease) increase in cash and cash equivalents	(30,475)	64,520
Cash and cash equivalents at beginning of period	281,453	306,224
Cash and cash equivalents at end of period	250,978	370,744
Supplemental disclosures
Cash paid for interest	12,656	9,635
Cash paid for income taxes	6,280	7,181
Noncash transactions:
Transfers of loans to other real estate owned	1,154	3,168
Financed sales of other real estate owned	418	237
Transfers of loans held for sale to loans held for investment	$ 442	$ 0