Borrowings (Long-Term Debt) (Details) - USD ($)		Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Notes and subordinated debt		$ 227,320,000	$ 227,320,000
Debt issuance cost on senior fixed-rate notes	[1]	(961,000)	(1,096,000)
Long-term debt		$ 225,514,000	$ 225,260,000
Long term debt, variable interest rate, percentage		3.94%	3.48%
London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Interest rate spread of LIBOR plus (as a percent)		2.95%
Long-term Debt [Member]
Debt Instrument [Line Items]
Discount on senior fixed-rate notes		$ (845,000)	$ (964,000)
Senior Notes [Member]
Debt Instrument [Line Items]
Debt instrument, stated interest rate, percentage		4.375%
Notes and subordinated debt		$ 150,000,000	150,000,000
Junior Subordinated Debt [Member]
Debt Instrument [Line Items]
Notes and subordinated debt	[2]	$ 77,320,000	$ 77,320,000

[1] In accordance with the adoption of ASU No. 2015-03, Interest-Imputation of Interest (Subtopic 835-30) - Simplifying the Presentation of Debt Issuance Costs, debt issuance cost is accounted for as a reduction to long-term debt. Previously debt issuance cost was included in accrued interest receivable and other assets within the accompanying Consolidated Balance Sheets.

[2] The interest rate on Webster Statutory Trust I floating-rate notes, which varies quarterly based on 3-month LIBOR plus 2.95%, was 3.94% at December 31, 2016 and 3.48% at December 31, 2015.