Accumulated Other Comprehensive Income (Reclassification out of AOCI) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Investment securities gains, net	$ 373	$ 721
Compensation and employee benefits	36,319	39,100
Total before tax	30,488	35,188
Income tax provision	(9,229)	(10,827)
Net income	21,259	24,361
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	373	721
Total before tax	373	721
Income tax provision	(135)	(262)
Net income	238	459
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	(167)	(44)
Total before tax	(167)	(44)
Income tax provision	61	16
Net income	$ (106)	$ (28)