Investment Securities (State And Municipal Obligations, By State And Economic Sector) (Details)	3 Months Ended
	Mar. 31, 2014 Y
Sector Classification, Texas [Member]
Investment [Line Items]
% of Portfolio	10.50%
Average Life (in years)	4.6
Average Rating (Moody's)	Aa1
Sector Classification, Florida [Member]
Investment [Line Items]
% of Portfolio	9.80%
Average Life (in years)	4.5
Average Rating (Moody's)	Aa3
Sector Classification, Washington [Member]
Investment [Line Items]
% of Portfolio	5.20%
Average Life (in years)	4.8
Average Rating (Moody's)	Aa2
Sector Classification New York [Member]
Investment [Line Items]
% of Portfolio	6.20%
Average Life (in years)	6.1
Average Rating (Moody's)	Aa2
Sector Classification Ohio [Member]
Investment [Line Items]
% of Portfolio	6.00%
Average Life (in years)	4.9
Average Rating (Moody's)	Aa2
Sector Classification, General Obligation [Member]
Investment [Line Items]
% of Portfolio	31.00%
Average Life (in years)	4.6
Average Rating (Moody's)	Aa2
Sector Classification, Housing [Member]
Investment [Line Items]
% of Portfolio	15.50%
Average Life (in years)	4.3
Average Rating (Moody's)	Aa1
Sector Classification, Lease [Member]
Investment [Line Items]
% of Portfolio	16.50%
Average Life (in years)	4.7
Average Rating (Moody's)	Aa3
Sector Classification, Transportation [Member]
Investment [Line Items]
% of Portfolio	13.60%
Average Life (in years)	4.3
Average Rating (Moody's)	A1
Sector Classification, Limited Tax [Member]
Investment [Line Items]
% of Portfolio	6.00%
Average Life (in years)	5.3
Average Rating (Moody's)	Aa1