Employee Benefits (Components of Net Periodic Benefit Cost) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income (Loss) (on a pre-tax basis):
Net (gain) loss		$ (3,098)	$ 1,591	$ 4,106
Prior service cost	[1]	(18)	(15)	(15)
Recognized in other comprehensive (loss) income		4,981	(154)	(3,055)
Qualified Pension Plan [Member]
Net Periodic Benefit Cost:
Service cost	[2]	2,244	2,149	2,148
Interest cost	[3]	2,715	2,673	2,576
Expected return on plan assets	[3]	(5,272)	(4,942)	(4,633)
Amortization of prior service credit	[3]	(23)	(23)	(23)
Recognized net actuarial loss	[3]	1,496	1,114	828
Net periodic benefit cost		1,160	971	896
Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income (Loss) (on a pre-tax basis):
Net (gain) loss		(4,342)	(1,798)	2,904
Prior service cost		23	23	23
Recognized in other comprehensive (loss) income		(4,319)	(1,775)	2,927
Total recognized in net periodic benefit cost and other comprehensive income (loss)		(3,159)	(804)	3,823
Non-Qualified Retirement Plans [Member]
Net Periodic Benefit Cost:
Service cost	[2]	108	129	122
Interest cost	[3]	475	428	432
Expected return on plan assets	[3]	0	0	0
Amortization of prior service credit	[3]	(1)	(1)	(1)
Recognized net actuarial loss	[3]	411	347	247
Net periodic benefit cost		993	903	800
Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income (Loss) (on a pre-tax basis):
Net (gain) loss		(663)	1,928	127
Prior service cost		1	1	1
Recognized in other comprehensive (loss) income		(662)	1,929	128
Total recognized in net periodic benefit cost and other comprehensive income (loss)		$ 331	$ 2,832	$ 928

[1] The pre-tax amounts are included in other expenses in the Consolidated Statements of Income.

[2] Included in salaries and employee benefits expense in the Consolidated Statements of Income.

[3] Included in other expenses in the Consolidated Statements of Income.