Summary Of Quarterly Financial Information (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Quarterly Financial Information Disclosure [Abstract]
Total interest income	$ 82,769	$ 82,665	$ 82,040	$ 81,417	$ 79,897	$ 77,133	$ 76,087	$ 74,925	$ 328,891	$ 308,042	$ 296,935
Total interest expense	950	971	1,030	1,053	1,133	913	963	985	4,004	3,994	5,840
Net Interest Income	81,819	81,694	81,010	80,364	78,764	76,220	75,124	73,940	324,887	304,048	291,095
Provision (recapture) for loan and lease losses	2,349	2,831	2,202	1,209	1,708	980	2,117	1,922	8,591	6,727	(101)
Noninterest income	24,745	22,499	21,462	22,767	15,185	15,930	14,627	14,008	91,473	59,750	26,700
Noninterest expense	66,877	64,067	68,471	66,734	64,154	59,982	57,764	57,386	266,149	239,286	230,886
Income before income taxes	37,338	37,295	31,799	35,188	28,087	31,188	29,870	28,640	141,620	117,785	87,010
Provision for income taxes	10,598	11,515	9,853	10,827	9,167	9,605	8,643	8,796	42,793	36,211	26,994
Net income	$ 26,740	$ 25,780	$ 21,946	$ 24,361	$ 18,920	$ 21,583	$ 21,227	$ 19,844	$ 98,827	$ 81,574	$ 60,016
Per Common Share
Earnings (basic)	$ 0.46	$ 0.45	$ 0.38	$ 0.42	$ 0.34	$ 0.41	$ 0.40	$ 0.38	$ 1.71	$ 1.53	$ 1.24
Earnings (diluted)	$ 0.46	$ 0.45	$ 0.38	$ 0.42	$ 0.34	$ 0.41	$ 0.40	$ 0.37	$ 1.71	$ 1.52	$ 1.21