Summary Of Significant Accounting Policies (Additional Cash Flow Information) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Summary Of Significant Accounting Policies [Abstract]
Cash paid for interest	$ 46,801	$ 56,924	$ 93,328
Cash paid for income tax	54,437	62,830	82,486
Loans foreclosed and transferred to other real estate owned and foreclosed assets	21,126	19,518	36,111
Loans to facilitate the sale of other real estate owned	75	480	4,699
Common stock/treasury stock issued to the Corporation's 401(k) stock purchase plan	1,360	9,770	5,017
Transfers of other real estate owned to premises and equipment			$ 976