Parent Company Only Financial Information (Balance Sheets) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Assets:
Cash and interest bearing deposits	$ 158,724	$ 258,799	$ 73,871	$ 125,270
Securities available for sale	1,845,864	1,578,434
Other investments, at cost	21,560	21,443
Other assets	123,869	100,256
TOTAL ASSETS	8,247,079	7,694,754	6,051,812
Liabilities and stockholders’ equity:
Short-term borrowings	306,459	293,898
Other borrowings	288,534	263,214
Accrued expenses and other liabilities	63,759	68,646
TOTAL LIABILITIES	7,506,163	7,031,581
Stockholders’ equity:
Common stock	26,120	22,436
Capital surplus	328,376	216,436
Retained earnings	416,109	348,630
Accumulated other comprehensive loss	(31,046)	(6,027)
Treasury stock	0	0
TOTAL STOCKHOLDERS' EQUITY	740,916	663,173	496,317	439,460
TOTAL LIABILITIES AND EQUITY	8,247,079	7,694,754
Parent
Assets:
Cash and interest bearing deposits	65,007	85,327	$ 124,387	$ 17,912
Securities available for sale	2,224	2,039
Other investments, at cost	195	235
Investment in subsidiaries	901,310	789,244
Other assets	26,154	26,102
Due from subsidiaries	6,000	6,000
TOTAL ASSETS	1,000,890	908,947
Liabilities and stockholders’ equity:
Short-term borrowings	0	15,000
Other borrowings	249,245	213,580
Accrued expenses and other liabilities	10,729	17,194
TOTAL LIABILITIES	259,974	245,774
Stockholders’ equity:
Preferred stock	1,357	81,698
Common stock	26,120	22,436
Capital surplus	328,376	216,436
Retained earnings	416,109	348,630
Accumulated other comprehensive loss	(31,046)	(6,027)
Treasury stock	0	0
TOTAL STOCKHOLDERS' EQUITY	740,916	663,173
TOTAL LIABILITIES AND EQUITY	$ 1,000,890	$ 908,947