Pension and Other Postretirement Benefits (Summary of Net Periodic Benefit Costs) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Webster Pension [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 40	$ 40	$ 30
Interest cost on projected benefit obligations	8,068	7,365	7,307
Expected return on plan assets	(11,495)	(11,114)	(10,069)
Amortization of prior service cost	0	0	0
Recognized net loss	2,781	6,355	6,103
Net periodic benefit cost (benefit)	(606)	2,646	3,371
Webster SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0	0
Interest cost on projected benefit obligations	364	289	316
Expected return on plan assets	0	0	0
Amortization of prior service cost	0	0	0
Recognized net loss	135	125	71
Net periodic benefit cost (benefit)	499	414	387
Other Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0	0
Interest cost on projected benefit obligations	139	109	177
Expected return on plan assets	0	0	0
Amortization of prior service cost	73	73	73
Recognized net loss	5	0	107
Net periodic benefit cost (benefit)	$ 217	$ 182	$ 357