Condensed Consolidated Statements of Cash Flows $ in Thousands	6 Months Ended
	Jun. 30, 2019 USD ($)	Jun. 30, 2018 USD ($)
Cash flows from operating activities:
Net income	$ 34,580	$ 43,172
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation	2,743	1,707
Provision for loan losses	3,198	2,261
Deferred income taxes	3,813	3,156
Net amortization of debt securities	1,189	956
Amortization of intangible assets	2,418	1,288
Loss (gain) on sale of investment securities	292	(9)
Mortgage loans originated for sale	(11,645)	(25,064)
Proceeds from mortgage loans sold	10,629	27,070
Gain on sale of other real estate	(48)	0
Gain on state tax credits, net	(107)	(316)
Share-based Payment Arrangement, Noncash Expense	1,907	1,631
Net accretion of loan discount	(4,702)	(793)
Changes in:
Accrued interest receivable	(6,942)	(3,739)
Accrued interest payable	354	154
Other assets	(9,697)	(809)
Other liabilities	(7,415)	1,203
Net cash provided by operating activities	20,567	51,868
Cash flows from investing activities:
Payments for Previous Acquisition	(23,377)	0
Increase in loans	(121,115)	(178,386)
Proceeds from the sale of securities, available for sale	263,298	1,451
Proceeds from the paydown or maturity of securities, available for sale	58,229	40,743
Proceeds from the paydown or maturity of securities, held to maturity	2,864	3,239
Proceeds from the redemption of other investments	31,138	22,728
Proceeds from the sale of state tax credits held for sale	2,252	1,940
Proceeds from the sale of other real estate	2,281	0
Payments for the purchase of:
Available for sale debt securities	(363,900)	(62,055)
Other investments	(43,589)	(33,719)
State tax credits held for sale	(1,852)	(4,636)
Fixed assets, net	(2,236)	(1,915)
Net cash used in investing activities	(196,007)	(210,610)
Cash flows from financing activities:
Net decrease in noninterest-bearing deposit accounts	(88,219)	(72,938)
Net increase (decrease) in interest-bearing deposit accounts	(21,615)	164,436
Proceeds from Federal Home Loan Bank advances	962,000	907,500
Repayments of Federal Home Loan Bank advances	(649,500)	(718,500)
Proceeds from Issuance of Long-term Debt	40,000	0
Repayments of Long-term Debt	(4,857)	0
Net decrease in other borrowings	(60,490)	(86,458)
Cash dividends paid on common stock	(7,798)	(5,086)
Payments for Repurchase of Common Stock	0	3,058
Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture	(1,233)	(3,220)
Net cash provided by financing activities	168,288	182,676
Net increase in cash and cash equivalents	(7,152)	23,934
Cash and cash equivalents, beginning of period	196,552	153,323
Cash and cash equivalents, end of period	189,400	177,257
Supplemental Cash Flow Information [Abstract]
Cash paid during the period for interest	32,036	19,670
Cash paid during the period for income taxes	11,915	780
Noncash transactions:
Transfer to other real estate owned in settlement of loans	$ 7,783	$ 0