Employee Benefits (Schedule Of Fair Value Of Pension Plan Assets) (Details) (USD $) In Thousands, unless otherwise specified			12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2011 Large-Cap Index Funds [Member]	Dec. 31, 2011 Small-Cap Index Funds [Member]	Dec. 31, 2011 International Index Funds [Member]	Dec. 31, 2011 Level 2 [Member]	Dec. 31, 2010 Level 2 [Member]	Dec. 31, 2011 Level 3 [Member]	Dec. 31, 2010 Level 3 [Member]	Dec. 31, 2011 Bank Collective Trust Funds - Equity Securities [Member] Large-Cap Index Funds [Member]		Dec. 31, 2010 Bank Collective Trust Funds - Equity Securities [Member] Large-Cap Index Funds [Member]		Dec. 31, 2011 Bank Collective Trust Funds - Equity Securities [Member] Small-Cap Index Funds [Member]		Dec. 31, 2010 Bank Collective Trust Funds - Equity Securities [Member] Small-Cap Index Funds [Member]		Dec. 31, 2011 Bank Collective Trust Funds - Equity Securities [Member] International Index Funds [Member]		Dec. 31, 2010 Bank Collective Trust Funds - Equity Securities [Member] International Index Funds [Member]		Dec. 31, 2011 Bank Collective Trust Funds - Equity Securities [Member] Level 2 [Member] Large-Cap Index Funds [Member]		Dec. 31, 2010 Bank Collective Trust Funds - Equity Securities [Member] Level 2 [Member] Large-Cap Index Funds [Member]		Dec. 31, 2011 Bank Collective Trust Funds - Equity Securities [Member] Level 2 [Member] Small-Cap Index Funds [Member]		Dec. 31, 2010 Bank Collective Trust Funds - Equity Securities [Member] Level 2 [Member] Small-Cap Index Funds [Member]		Dec. 31, 2011 Bank Collective Trust Funds - Equity Securities [Member] Level 2 [Member] International Index Funds [Member]		Dec. 31, 2010 Bank Collective Trust Funds - Equity Securities [Member] Level 2 [Member] International Index Funds [Member]		Dec. 31, 2010 Bank Collective Trust Funds - Equity Securities [Member] Level 3 [Member] Large-Cap Index Funds [Member]		Dec. 31, 2010 Bank Collective Trust Funds - Equity Securities [Member] Level 3 [Member] Small-Cap Index Funds [Member]		Dec. 31, 2010 Bank Collective Trust Funds - Equity Securities [Member] Level 3 [Member] International Index Funds [Member]		Dec. 31, 2011 Bank Collective Trust Funds - Fixed Income [Member] Bond Index Funds [Member]		Dec. 31, 2010 Bank Collective Trust Funds - Fixed Income [Member] Bond Index Funds [Member]		Dec. 31, 2011 Bank Collective Trust Funds - Fixed Income [Member] Short Term Investment Funds [Member]	Dec. 31, 2010 Bank Collective Trust Funds - Fixed Income [Member] Short Term Investment Funds [Member]	Dec. 31, 2011 Bank Collective Trust Funds - Fixed Income [Member] Level 2 [Member] Bond Index Funds [Member]		Dec. 31, 2010 Bank Collective Trust Funds - Fixed Income [Member] Level 2 [Member] Bond Index Funds [Member]		Dec. 31, 2010 Bank Collective Trust Funds - Fixed Income [Member] Level 2 [Member] Short Term Investment Funds [Member]	Dec. 31, 2010 Bank Collective Trust Funds - Fixed Income [Member] Level 3 [Member] Bond Index Funds [Member]		Dec. 31, 2011 Bank Collective Trust Funds - Fixed Income [Member] Level 3 [Member] Short Term Investment Funds [Member]	Dec. 31, 2010 Bank Collective Trust Funds - Fixed Income [Member] Level 3 [Member] Short Term Investment Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 35,478	$ 32,867				$ 35,059	$ 32,400	$ 419	$ 467	$ 17,562	[1]	$ 15,007	[1]	$ 2,324	[2]	$ 3,220	[2]	$ 3,367	[3]	$ 3,216	[3]	$ 17,562	[1]	$ 15,007	[1]	$ 2,324	[2]	$ 3,220	[2]	$ 3,367	[3]	$ 3,216	[3]		[1]		[2]		[3]	$ 11,806	[4]	$ 10,957	[4]	$ 419	$ 467	$ 11,806	[4]	$ 10,957	[4]			[4]	$ 419	$ 467
Percentage of assets invested in specified company type			90.00%	95.00%	90.00%

[1] Over 90% of the assets of these funds are invested in large-cap U.S. companies. The remainder of the assets of these funds is invested in cash reserves.

[2] Over 95% of the assets of these funds are invested in small-cap U.S. companies. The remainder of the assets of these funds is invested in cash reserves.

[3] At least 90% of the assets of these funds are invested in international companies in developed markets (excluding the U.S. and Canada). The remainder of the assets of these funds is invested in cash reserves.

[4] This category represents investment grade bonds of U.S. issuers, including U.S. Treasury notes.