Goodwill and Other Intangible Assets (Gross Carrying Value And Accumulated Amortization Of Other Intangible Assets) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 92,420	$ 49,420
Accumulated Amortization	(53,094)	(46,754)
Net Carrying Amount	39,326	2,666
HSA Bank [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	43,000	0
Accumulated Amortization	(4,817)	0
Net Carrying Amount	38,183	0
Core Deposits [Member] | Community Banking [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	49,420	49,420
Accumulated Amortization	(48,277)	(46,754)
Net Carrying Amount	1,143	2,666
Core Deposits [Member] | HSA Bank [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	22,000	0
Accumulated Amortization	(3,269)	0
Net Carrying Amount	$ 18,731	0
Finite-Lived Intangible Asset, Useful Life (in years)	9 years
Customer Relationships [Member] | HSA Bank [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 21,000	0
Accumulated Amortization	(1,548)	0
Net Carrying Amount	$ 19,452	$ 0
Customer-Related Intangible Assets [Member] | HSA Bank [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life (in years)	13 years