PARENT ONLY CONDENSED FINANCIAL STATEMENTS - Parent Only Condensed Statement Of Cash Flows - (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Mar. 31, 2015	Jun. 30, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating Activities
Net income	$ 11,744	$ 11,696	$ 6,117	$ 8,766	$ 9,108	$ 9,111	$ 7,663	$ 9,660	$ 38,323	$ 35,542	$ 28,996
Change in other assets and liabilities									(2,294)	1,402	4,172
Net cash provided by operating activities									47,262	53,392	43,358
Investing Activities
Proceeds from sales of securities available for sale									88,203	147,109	27,131
Cash paid for bank acquisitions, net									11,289	(57,083)	10,686
Purchases of equipment									(14,068)	(7,794)	(5,593)
Net cash used by investing activities									(179,227)	(171,539)	(48,972)
Financing Activities
Proceeds from exercise of stock options									1,556	294	66
Proceeds from term debt									30,000
Purchase of treasury shares									(1,045)	(3,527)	(319)
Repayment of subordinated debentures, net											(5,000)
Repayment on term debt									(11,667)
Cash dividends on common stock									(14,296)	(11,680)	(8,726)
Net cash provided by financing activities									150,939	123,240	6,779
Net change in cash and cash equivalents									18,974	5,093	1,165
Cash and cash equivalents, beginning of year				67,578			62,485		67,578	62,485	61,320
Cash and cash equivalents, end of period	86,552				67,578				86,552	67,578	62,485
Parent Company
Operating Activities
Net income									38,323	35,542	28,996
Undistributed (income)/loss of subsidiaries									(3,147)	(12,010)	(10,636)
Change in other assets and liabilities									1,953	1,896	3,862
Net cash provided by operating activities									37,129	25,428	22,222
Investing Activities
Proceeds from sales of securities available for sale									19	0	750
Cash paid for bank acquisitions, net									(45,188)	0	(13,935)
Purchases of equipment									(1,215)	(1,991)	(403)
Net cash used by investing activities									(46,384)	(1,991)	(13,588)
Financing Activities
Proceeds from exercise of stock options									1,783	294	66
Proceeds from term debt									30,000
Purchase of treasury shares									(1,045)	(3,527)	(319)
Repayment of subordinated debentures, net										0	(5,000)
Repayment on term debt									(11,667)
Cash dividends on common stock									(14,296)	(11,680)	(8,726)
Net cash provided by financing activities									4,775	(14,913)	(13,979)
Net change in cash and cash equivalents									(4,480)	8,524	(5,345)
Cash and cash equivalents, beginning of year				$ 14,846			$ 6,322		14,846	6,322	11,667
Cash and cash equivalents, end of period	$ 10,366				$ 14,846				$ 10,366	$ 14,846	$ 6,322