Components of Net Periodic Pension Cost (Schedule of Changes as a result of ASU 2017-07) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other components of net periodic pension expense	$ 7	$ 62
Salaries and employee benefits	$ 9,672	8,144
Accounting Standards Update 2017-07 [Member] | Previously Reported [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other components of net periodic pension expense
Salaries and employee benefits		$ 8,206