Parent Company Only Financial Information (Balance Sheets) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Assets:
Cash and interest bearing deposits	$ 378,734	$ 273,630
Other assets	186,755	114,841
TOTAL ASSETS	13,209,597	11,408,006
Liabilities and stockholders’ equity:
Other borrowings	275,773	274,905
Accrued expenses and other liabilities	128,730	78,078
TOTAL LIABILITIES	11,631,460	10,082,831
Stockholders’ equity:
Common stock	36,704	34,477
Capital surplus	839,857	743,095
Retained earnings	702,502	579,252
Accumulated other comprehensive loss	(926)	(31,649)
TOTAL STOCKHOLDERS' EQUITY	1,578,137	1,325,175	$ 991,457	$ 740,916
TOTAL LIABILITIES AND EQUITY	13,209,597	11,408,006
Parent
Assets:
Cash and interest bearing deposits	61,866	39,666
Investment in subsidiaries	1,765,995	1,538,766
Other assets	49,002	30,321
Due from subsidiaries	0	6,000
TOTAL ASSETS	1,876,863	1,614,753
Liabilities and stockholders’ equity:
Other borrowings	271,046	269,553
Accrued expenses and other liabilities	27,680	20,025
TOTAL LIABILITIES	298,726	289,578
Stockholders’ equity:
Common stock	36,704	34,477
Capital surplus	839,857	743,095
Retained earnings	702,502	579,252
Accumulated other comprehensive loss	(926)	(31,649)
TOTAL STOCKHOLDERS' EQUITY	1,578,137	1,325,175
TOTAL LIABILITIES AND EQUITY	$ 1,876,863	$ 1,614,753