Benefit Plan (Components Of Net Periodic Benefit Expense) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Defined Benefit Plan Disclosure [Line Items]
Other components of net periodic benefit income	$ 1,705	$ 1,448	$ 5,115	$ 4,344
Total other income	24,064	23,537	74,209	63,191
Employee Benefits and Share-based Compensation	7,653	5,943	22,312	18,617
Other expense	1,758	2,925	5,333	6,330
Total other expense	59,316	51,259	166,158	149,723
Service cost	1,637	1,317	4,911	3,951
Interest cost	1,309	1,271	3,927	3,813
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	(68)	(131)	(204)	(393)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	1,637	1,317	4,911	3,951
Interest cost	1,309	1,271	3,927	3,813
Expected return on plan assets	(3,354)	(2,863)	(10,062)	(8,589)
Amortization of prior service cost	0	0	0	0
Recognized net actuarial loss	340	144	1,020	432
Benefit expense	(68)	(131)	(204)	(393)
Pension plan contributions	0	0	0	0
Supplemental Employee Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	157	185	635	555
Interest cost	188	161	349	483
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	345	346	984	1,038
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	157	185	635	555
Interest cost	188	161	349	483
Benefit expense	$ 345	346	$ 984	1,038
Restatement Adjustment [Member] | Accounting Standards Update 2017-07 [Member]
Defined Benefit Plan Disclosure [Line Items]
Other components of net periodic benefit income		1,448		4,344
Total other income		23,537		63,191
Employee Benefits and Share-based Compensation		5,943		18,617
Other expense		2,925		6,330
Total other expense		51,259		149,723
Previously Reported [Member] | Accounting Standards Update 2017-07 [Member]
Defined Benefit Plan Disclosure [Line Items]
Other components of net periodic benefit income		0		0
Total other income		22,089		58,847
Employee Benefits and Share-based Compensation		4,656		14,756
Other expense		2,764		5,847
Total other expense		$ 49,811		$ 145,379