Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Statement of Cash Flows [Abstract]
Net cash provided by operating activities	$ 81,423	$ 59,238
Investing Activities
Proceeds from maturities, repayments, and calls of securities available-for-sale	158,946	174,937
Proceeds from sales of securities available-for-sale	241,137	40,043
Purchases of securities available-for-sale	(172,451)	(532,934)
Proceeds from maturities, repayments, and calls of securities held-to-maturity	4,948	4,360
Purchases of securities held-to-maturity	(10)	(16)
Net purchases of FHLB stock	(3,955)	(3,651)
Net increase in loans	(225,537)	(432,283)
Premiums paid on BOLI, net of proceeds from claims	(6)	1,599
Proceeds from sales of OREO	8,476	3,852
Proceeds from sales of premises, furniture, and equipment	7,056	3,213
Purchases of premises, furniture, and equipment	(6,619)	(7,536)
Net cash received from acquisitions	41,717	57,347
Net cash provided by (used in) investing activities	53,702	(691,069)
Financing Activities
Net increase in deposit accounts	147,243	278,657
Net (decrease) increase in borrowed funds	(239,675)	282,232
Payments for the maturity of subordinated debt	0	(38,500)
Cash dividends paid	(16,485)	(14,123)
Restricted stock activity	(4,004)	(2,248)
Net cash (used in) provided by financing activities	(112,921)	506,018
Net increase (decrease) in cash and cash equivalents	22,204	(125,813)
Cash and cash equivalents at beginning of period	262,148	381,202
Cash and cash equivalents at end of period	284,352	255,389
Supplemental Disclosures of Cash Flow Information:
Income taxes (refunded) paid	(958)	7,427
Interest paid to depositors and creditors	16,381	13,269
Dividends declared, but unpaid	9,165	7,595
Stock issued for acquisitions, net of issuance costs	534,090	54,896
Non-cash transfers of loans to OREO	1,982	3,675
Non-cash transfers of loans held-for-investment to loans held-for-sale	$ 31,564	$ 63,709