Time Certificates of Deposit (Schedule of Time Certifcates of Deposit Maturities) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Schedule Maturity Abstract]
Time Deposits Scheduled Maturity, Next Twelve Months	$ 479,914
Time Deposits Scheduled Maturity, Year Two	323,597
Time Deposits Scheduled Maturity, Year Three	90,282
Time Deposits Scheduled Maturity, Year Four	59,263
Time Deposits Scheduled Maturity, Year Five	61,991
Time Deposits Scheduled Maturity, Thereafter	48
Time deposits	$ 1,015,095	$ 961,613
Weighted Average Rate [Abstract]
Time Deposits Weighted Average Rate, Next Twelve Months	0.96%
Time Deposits Weighted Average Rate, Year Two	1.51%
Time Deposits Weighted Average Rate, Year Three	1.54%
Time Deposits Weighted Average Rate, Year Four	1.77%
Time Deposits Weighted Average Rate, Year Five	1.94%
Time Deposits Weighted Average Rate, Thereafter	1.30%
Total Time Deposits Weighted Average Rate	1.30%