Accumulated Other Comprehensive Income (Reclassification out of AOCI) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Investment securities gains, net			$ 552	$ 462
Compensation and employee benefits	32,559	33,287	94,961	90,597
Total before tax	31,188	20,010	89,698	59,126
Income tax provision	(9,605)	(6,734)	(27,044)	(19,083)
Net of tax	21,583	13,276	62,654	40,043
Reclassification out of Accumulated Other Comprehensive Income [Member] | Unrealized Gains and Losses on Available-for-Sale Securities [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Investment securities gains, net	33	0	552	462
Total before tax	33	0	552	462
Income tax provision	(12)	0	(200)	(163)
Net of tax	21	0	352	299
Reclassification out of Accumulated Other Comprehensive Income [Member] | Unrealized Gains and Losses on Pension Plan Liability [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Compensation and employee benefits	(36)	(92)	(111)	(276)
Total before tax	(36)	(92)	(111)	(276)
Income tax provision	13	33	40	98
Net of tax	$ (23)	$ (59)	$ (71)	$ (178)