The amount by which the fair value of an investment is less than the amortized cost basis or carrying amount of that investment at the balance sheet date and the decline in fair value is deemed to be other than temporary, before considering whether or not such amount is recognized in earnings or other comprehensive income.

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+ Details

Parent Company Financial Statements (Details Textual) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Condensed Financial Statements, Captions [Line Items]
Rate of interest of subordinated notes	3.85%
Maturity date of Senior notes	Jan. 31, 2068
Parent Company Financial Statements (Textual) [Abstract]
Total other-than-temporary impairment ("OTTI") losses	$ (72,915)	$ (115,947)	$ (264,363)
5.375% senior notes of M&T issued in 2007 [Member]
Condensed Financial Statements, Captions [Line Items]
Senior Notes	$ 300,000
Rate of interest of subordinated notes	5.375%
Maturity date of Senior notes	May 01, 2012