Long-Term Debt (Schedule Of Long-Term Debt) (Detail) (USD $)	0 Months Ended	9 Months Ended		9 Months Ended			9 Months Ended		9 Months Ended		9 Months Ended
	Feb. 08, 2012	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2012 Webster Capital Trust IV [Member]	Jul. 18, 2012 Webster Capital Trust IV [Member]	Dec. 31, 2011 Webster Capital Trust IV [Member]	Sep. 30, 2012 Webster Statutory Trust I [Member]	Dec. 31, 2011 Webster Statutory Trust I [Member]	Sep. 30, 2012 Senior Fixed-Rate Notes [Member]	Dec. 31, 2011 Senior Fixed-Rate Notes [Member]	Sep. 30, 2012 Subordinated Fixed-Rate Notes [Member]	Dec. 31, 2011 Subordinated Fixed-Rate Notes [Member]
Debt Instrument [Line Items]
Maturity date				Jan. 01, 2037			Jan. 01, 2033		Jan. 01, 2014		Jan. 01, 2013
Stated interest rate		7.65%		7.65%			3.339%		5.125%		5.875%
Senior fixed-rate notes									$ 150,000,000	$ 150,000,000
Subordinated fixed-rate notes	74,900,000										102,579,000	177,480,000
Total junior subordinated debt		77,320,000	213,390,000	0	136,100,000	136,070,000	77,320,000	77,320,000
Total notes and subordinated debt		329,899,000	540,870,000
Unamortized discount, net		111,000	192,000
Hedge accounting adjustments		5,890,000	11,911,000
Total long-term debt		335,678,000	552,589,000
Accrued and unpaid interest paid from cash on hand	$ 77,800,000	$ 137,000,000
Interest rate spread of LIBOR plus							2.95%
Long-term debt, variable interest rate							3.339%	3.502%