Securities (Schedule of Contractual Maturities of Investment Securities Available for Sale) (Details) $ in Thousands	Dec. 31, 2015 USD ($)
Available-for-sale Securities [Abstract]
Due within one year, Amortized Cost	$ 22,191
Due after one year through five years, Amortized Cost	458,889
Due after five years through ten years, Amortized Cost	702,234
Due after ten years, Amortized Cost	969,012
Total investment securities available-for-sale, Amortized Cost	2,157,610
Due within one year, Fair Value	22,418
Due after one year through five years, Fair Value	458,372
Due after five years through ten years, Fair Value	703,088
Due after ten years, Fair Value	968,699
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Amortized Cost Basis	5,284
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Fair Value	5,117
Total investment securities available-for-sale, Fair Value	$ 2,157,694