Loans and Allowance for Loan Losses (Schedule Of Impaired Loans) (Details) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Financing Receivable, Impaired [Line Items]
Recorded Investment, With no related allowance recorded	$ 34,664,000		$ 28,751,000
Recorded Investment, With allowance recorded	200,092,000		220,745,000
Recorded Investment	234,756,000		249,496,000
Unpaid Principal Balance, With no related allowance recorded	48,938,000		40,794,000
Unpaid Principal Balance, With allowance recorded	202,743,000		223,512,000
Unpaid Principal Balance	251,681,000		264,306,000
Related Allowance, With no related allowance recorded	0		0
Related Allowance, With allowance recorded	19,707,000		18,111,000
Related Allowance	19,707,000		18,111,000
Average Recorded Investment, With no related allowance recorded	30,046,000		26,433,000
Average Recorded Investment, With allowance recorded	205,507,000		248,082,000
Average Recorded Investment	235,553,000	$ 298,600,000	274,515,000
Interest Income Recognized, With no related allowance recorded	0		0
Interest Income Recognized, With allowance recorded	1,689,000		8,196,000
Interest Income Recognized	1,689,000	$ 0	8,196,000
Commercial Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment, With no related allowance recorded	2,677,000		3,490,000
Recorded Investment, With allowance recorded	76,526,000		87,920,000
Recorded Investment	79,203,000		91,410,000
Unpaid Principal Balance, With no related allowance recorded	9,777,000		10,975,000
Unpaid Principal Balance, With allowance recorded	76,582,000		87,926,000
Unpaid Principal Balance	86,359,000		98,901,000
Related Allowance, With no related allowance recorded	0		0
Related Allowance, With allowance recorded	6,917,000		7,916,000
Related Allowance	6,917,000		7,916,000
Average Recorded Investment, With no related allowance recorded	3,200,000		9,803,000
Average Recorded Investment, With allowance recorded	77,307,000		108,091,000
Average Recorded Investment	80,507,000		117,894,000
Interest Income Recognized, With no related allowance recorded	0		0
Interest Income Recognized, With allowance recorded	600,000		3,286,000
Interest Income Recognized	600,000		3,286,000
Investment Properties [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment, With no related allowance recorded	0		748,000
Recorded Investment, With allowance recorded	29,401,000		31,489,000
Recorded Investment	29,401,000		32,237,000
Unpaid Principal Balance, With no related allowance recorded	0		793,000
Unpaid Principal Balance, With allowance recorded	29,401,000		31,489,000
Unpaid Principal Balance	29,401,000		32,282,000
Related Allowance, With no related allowance recorded	0		0
Related Allowance, With allowance recorded	1,749,000		2,044,000
Related Allowance	1,749,000		2,044,000
Average Recorded Investment, With no related allowance recorded	492,000		2,013,000
Average Recorded Investment, With allowance recorded	29,886,000		42,659,000
Average Recorded Investment	30,378,000		44,672,000
Interest Income Recognized, With no related allowance recorded	0		0
Interest Income Recognized, With allowance recorded	291,000		1,436,000
Interest Income Recognized	291,000		1,436,000
1-4 Family Properties [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment, With no related allowance recorded	581,000		643,000
Recorded Investment, With allowance recorded	15,964,000		23,642,000
Recorded Investment	16,545,000		24,285,000
Unpaid Principal Balance, With no related allowance recorded	2,909,000		2,939,000
Unpaid Principal Balance, With allowance recorded	15,964,000		23,649,000
Unpaid Principal Balance	18,873,000		26,588,000
Related Allowance, With no related allowance recorded	0		0
Related Allowance, With allowance recorded	441,000		769,000
Related Allowance	441,000		769,000
Average Recorded Investment, With no related allowance recorded	612,000		1,021,000
Average Recorded Investment, With allowance recorded	17,857,000		39,864,000
Average Recorded Investment	18,469,000		40,885,000
Interest Income Recognized, With no related allowance recorded	0		0
Interest Income Recognized, With allowance recorded	136,000		855,000
Interest Income Recognized	136,000		855,000
Land and Development [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment, With no related allowance recorded	2,096,000		2,099,000
Recorded Investment, With allowance recorded	31,161,000		32,789,000
Recorded Investment	33,257,000		34,888,000
Unpaid Principal Balance, With no related allowance recorded	6,868,000		7,243,000
Unpaid Principal Balance, With allowance recorded	31,217,000		32,788,000
Unpaid Principal Balance	38,085,000		40,031,000
Related Allowance, With no related allowance recorded	0		0
Related Allowance, With allowance recorded	4,727,000		5,103,000
Related Allowance	4,727,000		5,103,000
Average Recorded Investment, With no related allowance recorded	2,096,000		6,769,000
Average Recorded Investment, With allowance recorded	29,564,000		25,568,000
Average Recorded Investment	31,660,000		32,337,000
Interest Income Recognized, With no related allowance recorded	0		0
Interest Income Recognized, With allowance recorded	173,000		995,000
Interest Income Recognized	173,000		995,000
Commercial and Industrial [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment, With no related allowance recorded	30,179,000		23,466,000
Recorded Investment, With allowance recorded	90,291,000		97,094,000
Recorded Investment	120,470,000		120,560,000
Unpaid Principal Balance, With no related allowance recorded	37,156,000		27,954,000
Unpaid Principal Balance, With allowance recorded	92,886,000		99,855,000
Unpaid Principal Balance	130,042,000		127,809,000
Related Allowance, With no related allowance recorded	0		0
Related Allowance, With allowance recorded	11,085,000		8,384,000
Related Allowance	11,085,000		8,384,000
Average Recorded Investment, With no related allowance recorded	25,047,000		14,715,000
Average Recorded Investment, With allowance recorded	93,643,000		104,268,000
Average Recorded Investment	118,690,000		118,983,000
Interest Income Recognized, With no related allowance recorded	0		0
Interest Income Recognized, With allowance recorded	689,000		3,161,000
Interest Income Recognized	689,000		3,161,000
Commercial, Financial and Agricultural [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment, With no related allowance recorded	20,267,000		17,958,000
Recorded Investment, With allowance recorded	47,190,000		43,386,000
Recorded Investment	67,457,000		61,344,000
Unpaid Principal Balance, With no related allowance recorded	24,000,000		20,577,000
Unpaid Principal Balance, With allowance recorded	49,739,000		45,913,000
Unpaid Principal Balance	73,739,000		66,490,000
Related Allowance, With no related allowance recorded	0		0
Related Allowance, With allowance recorded	5,994,000		5,687,000
Related Allowance	5,994,000		5,687,000
Average Recorded Investment, With no related allowance recorded	17,495,000		6,321,000
Average Recorded Investment, With allowance recorded	44,084,000		51,968,000
Average Recorded Investment	61,579,000		58,289,000
Interest Income Recognized, With no related allowance recorded	0		0
Interest Income Recognized, With allowance recorded	351,000		1,215,000
Interest Income Recognized	351,000		1,215,000
Owner-Occupied [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment, With no related allowance recorded	9,912,000		5,508,000
Recorded Investment, With allowance recorded	43,101,000		53,708,000
Recorded Investment	53,013,000		59,216,000
Unpaid Principal Balance, With no related allowance recorded	13,156,000		7,377,000
Unpaid Principal Balance, With allowance recorded	43,147,000		53,942,000
Unpaid Principal Balance	56,303,000		61,319,000
Related Allowance, With no related allowance recorded	0		0
Related Allowance, With allowance recorded	5,091,000		2,697,000
Related Allowance	5,091,000		2,697,000
Average Recorded Investment, With no related allowance recorded	7,552,000		8,394,000
Average Recorded Investment, With allowance recorded	49,559,000		52,300,000
Average Recorded Investment	57,111,000		60,694,000
Interest Income Recognized, With no related allowance recorded	0		0
Interest Income Recognized, With allowance recorded	338,000		1,946,000
Interest Income Recognized	338,000		1,946,000
Retail [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment, With no related allowance recorded	1,808,000		1,795,000
Recorded Investment, With allowance recorded	33,275,000		35,731,000
Recorded Investment	35,083,000		37,526,000
Unpaid Principal Balance, With no related allowance recorded	2,005,000		1,865,000
Unpaid Principal Balance, With allowance recorded	33,275,000		35,731,000
Unpaid Principal Balance	35,280,000		37,596,000
Related Allowance, With no related allowance recorded	0		0
Related Allowance, With allowance recorded	1,705,000		1,811,000
Related Allowance	1,705,000		1,811,000
Average Recorded Investment, With no related allowance recorded	1,799,000		1,915,000
Average Recorded Investment, With allowance recorded	34,557,000		35,723,000
Average Recorded Investment	36,356,000		37,638,000
Interest Income Recognized, With no related allowance recorded	0		0
Interest Income Recognized, With allowance recorded	400,000		1,749,000
Interest Income Recognized	400,000		1,749,000
Home Equity Lines [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment, With no related allowance recorded	1,064,000		1,051,000
Recorded Investment, With allowance recorded	8,913,000		9,638,000
Recorded Investment	9,977,000		10,689,000
Unpaid Principal Balance, With no related allowance recorded	1,064,000		1,051,000
Unpaid Principal Balance, With allowance recorded	8,913,000		9,638,000
Unpaid Principal Balance	9,977,000		10,689,000
Related Allowance, With no related allowance recorded	0		0
Related Allowance, With allowance recorded	977,000		971,000
Related Allowance	977,000		971,000
Average Recorded Investment, With no related allowance recorded	1,055,000		1,045,000
Average Recorded Investment, With allowance recorded	9,207,000		9,668,000
Average Recorded Investment	10,262,000		10,713,000
Interest Income Recognized, With no related allowance recorded	0		0
Interest Income Recognized, With allowance recorded	236,000		432,000
Interest Income Recognized	236,000		432,000
Consumer Mortgages [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment, With no related allowance recorded	744,000		744,000
Recorded Investment, With allowance recorded	19,541,000		20,953,000
Recorded Investment	20,285,000		21,697,000
Unpaid Principal Balance, With no related allowance recorded	941,000		814,000
Unpaid Principal Balance, With allowance recorded	19,541,000		20,953,000
Unpaid Principal Balance	20,482,000		21,767,000
Related Allowance, With no related allowance recorded	0		0
Related Allowance, With allowance recorded	584,000		673,000
Related Allowance	584,000		673,000
Average Recorded Investment, With no related allowance recorded	744,000		870,000
Average Recorded Investment, With allowance recorded	20,433,000		20,993,000
Average Recorded Investment	21,177,000		21,863,000
Interest Income Recognized, With no related allowance recorded	0		0
Interest Income Recognized, With allowance recorded	91,000		1,014,000
Interest Income Recognized	91,000		1,014,000
Credit Card Receivable [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment, With no related allowance recorded	0		0
Recorded Investment, With allowance recorded	0		0
Recorded Investment	0		0
Unpaid Principal Balance, With no related allowance recorded	0		0
Unpaid Principal Balance, With allowance recorded	0		0
Unpaid Principal Balance	0		0
Related Allowance, With no related allowance recorded	0		0
Related Allowance, With allowance recorded	0		0
Related Allowance	0		0
Average Recorded Investment, With no related allowance recorded	0		0
Average Recorded Investment, With allowance recorded	0		0
Average Recorded Investment	0		0
Interest Income Recognized, With no related allowance recorded	0		0
Interest Income Recognized, With allowance recorded	0		0
Interest Income Recognized	0		0
Other Consumer Loans [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment, With no related allowance recorded	0		0
Recorded Investment, With allowance recorded	4,821,000		5,140,000
Recorded Investment	4,821,000		5,140,000
Unpaid Principal Balance, With no related allowance recorded	0		0
Unpaid Principal Balance, With allowance recorded	4,821,000		5,140,000
Unpaid Principal Balance	4,821,000		5,140,000
Related Allowance, With no related allowance recorded	0		0
Related Allowance, With allowance recorded	144,000		167,000
Related Allowance	144,000		167,000
Average Recorded Investment, With no related allowance recorded	0		0
Average Recorded Investment, With allowance recorded	4,917,000		5,062,000
Average Recorded Investment	4,917,000		5,062,000
Interest Income Recognized, With no related allowance recorded	0		0
Interest Income Recognized, With allowance recorded	73,000		303,000
Interest Income Recognized	$ 73,000		$ 303,000