Securities (Securities by Contractual Maturity) (Details) - USD ($) $ in Thousands	Mar. 31, 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	$ 61,790
Available for sale debt securities maturities 1-5 years amortized cost	249,476
Available for sale debt securities maturities 5-10 years amortized cost	249,319
Available for sale debt securities maturities after 10 years amortized cost	204,332
Available for sale debt securities maturities total amortized cost	764,917
Available for sale debt securities maturities within 1 year fair value	61,370
Available for sale debt securities maturities 1-5 years fair value	246,868
Available for sale debt securities maturities 5-10 years fair value	245,182
Available for sale debt securities maturities after 10 years fair value	201,300
Available for sale debt securities fair value	754,720
Held to maturity debt securities maturities within 1 year amortized cost	1,851
Held to maturity debt securities maturities 1-5 years amortized cost	5,926
Held to maturity debt securities maturities 5-10 years amortized cost	4,802
Held to maturity debt securities maturities after 10 years amortized cost	2,142
Held to maturity securities	14,721	$ 15,633
Held to maturity debt securities maturities within 1 year fair value	1,881
Held to maturity debt securities maturities 1-5 years fair value	6,024
Held to maturity debt securities maturities 5-10 years fair value	4,882
Held to maturity debt securities maturities after 10 years fair value	2,178
Held to maturity securities fair value	$ 14,965	$ 15,920