Long-Term Debt (Schedule Of Long-Term Debt) (Detail) (USD $)						0 Months Ended
	Sep. 30, 2014		Dec. 31, 2013		Sep. 30, 2014 London Interbank Offered Rate (LIBOR) [Member]	Feb. 11, 2014 Senior fixed-rate notes [Member]	Sep. 30, 2014 Junior Subordinated Debt [Member]		Dec. 31, 2013 Junior Subordinated Debt [Member]		Sep. 30, 2014 4.375% Maturing 2024 [Member] Senior fixed-rate notes [Member]		Feb. 11, 2014 4.375% Maturing 2024 [Member] Senior fixed-rate notes [Member]	Dec. 31, 2013 4.375% Maturing 2024 [Member] Senior fixed-rate notes [Member]		Sep. 30, 2014 5.125% Maturing 2014 [Member] Senior fixed-rate notes [Member]		Dec. 31, 2013 5.125% Maturing 2014 [Member] Senior fixed-rate notes [Member]
Debt Instrument [Line Items]
Stated interest rate													4.375%			5.125%	[1]
Senior Notes											$ 150,000,000	[1]		$ 0	[1]	$ 0		$ 150,000,000
Junior Subordinated Notes							77,320,000	[2]	77,320,000	[2]
Total notes and subordinated debt	227,320,000		227,320,000
Unamortized discount, net	(1,112,000)	[3]	(21,000)	[3]
Deferred (Gain) Loss on Discontinuation of Fair Value Hedge	0	[3]	1,066,000	[3]
Long-term debt	226,208,000		228,365,000
Face amount						150,000,000.0
Proceeds from issuance of senior debt						$ 148,000,000
Interest rate spread of LIBOR plus					2.95%
Variable interest rate	3.185%		3.194%

[1] On February 11, 2014, Webster completed an underwritten public offering of $150.0 million aggregate principal amount of 4.375% senior notes maturing February 15, 2024. Webster received net proceeds of $148.0 million from the public offering

[2] The interest rate on Webster Statutory Trust I floating-rate notes, which varies quarterly based on 3-month LIBOR plus 2.95%, was 3.185% at September 30, 2014 and 3.194% at December 31, 2013

[3] Related to senior fixed-rate notes due 2024 at September 30, 2014 and senior fixed-rate notes due 2014 at December 31, 2013