Retirement Benefit Plans (Amount Recognized in the Consolidated Balance Sheets) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Webster Pension [Member]
Defined Benefit Plan Disclosure [Line Items]
Accrued expenses and other liabilities	$ (42,276)	$ (37,572)
Webster SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Accrued expenses and other liabilities	(10,518)	(10,041)
Postretirement Health Coverage [Member]
Defined Benefit Plan Disclosure [Line Items]
Accrued expenses and other liabilities	$ (3,853)	$ (4,133)