Accumulated Other Comprehensive Income (Reclassification out of AOCI) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Investment securities gains, net	$ 296	$ 92	$ 519	$ 462
Compensation and employee benefits	31,064	35,657	62,402	57,310
Total before tax	29,870	22,005	58,510	39,116
Income tax provision	(8,643)	(7,414)	(17,439)	(12,349)
Net of tax	21,227	14,591	41,071	26,767
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	296	92	519	462
Total before tax	296	92	519	462
Income tax provision	(107)	(33)	(188)	(163)
Net of tax	189	59	331	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	(37)	(92)	(74)	(184)
Total before tax	(37)	(92)	(74)	(184)
Income tax provision	13	32	26	65
Net of tax	$ (24)	$ (60)	$ (48)	$ (119)