Other Comprehensive Income (Reclassifications from AOCI) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
Compensation and employee benefits	$ 31,195	$ 28,369
Income tax expense	5,257	7,689
Net income	(14,931)	(30,890)
Reclassification adjustment | Post-retirement obligations
Accumulated Other Comprehensive Income (Loss) [Line Items]
Compensation and employee benefits	112	47
Income tax expense	(28)	(13)
Net income	$ 84	$ 34