Securities (Securities by Contractual Maturity) (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Schedule of Available for Sale and Held to Maturty Securities [Line Items]
Available for sale debt securities maturities within 1 year amortized cost	$ 64,607
Available for sale debt securities maturities 1-5 years amortized cost	249,039
Available for sale debt securities maturities 5-10 years amortized cost	251,102
Available for sale debt securities maturities after 10 years amortized cost	192,033
Available for sale debt securities maturities total amortized cost	756,781
Available for sale debt securities maturities within 1 year fair value	64,271
Available for sale debt securities maturities 1-5 years fair value	246,979
Available for sale debt securities maturities 5-10 years fair value	247,891
Available for sale debt securities maturities after 10 years fair value	190,345
Available for sale debt securities fair value	749,486
Held to maturity debt securities maturities within 1 year amortized cost	2,422
Held to maturity debt securities maturities 1-5 years amortized cost	6,586
Held to maturity debt securities maturities 5-10 years amortized cost	3,876
Held to maturity debt securities maturities after 10 years amortized cost	1,058
Held to maturity securities	13,942	$ 15,633
Held to maturity debt securities maturities within 1 year fair value	2,472
Held to maturity debt securities maturities 1-5 years fair value	6,723
Held to maturity debt securities maturities 5-10 years fair value	3,956
Held to maturity debt securities maturities after 10 years fair value	1,080
Held to maturity securities fair value	$ 14,231	$ 15,920