Securities (Securities by Contractual Maturity) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Schedule of Available for Sale and Held to Maturity Securities [Line Items]
Available for sale debt securities maturities wIthin 1 year amortized cost	$ 75,499
Available for sale debt securities maturities 1-5 years amortized cost	254,974
Available for sale debt securities maturities 5-10 years amortized cost	239,622
Available for sale debt securities maturities after 10 years amortized cost	180,650
Available for sale securities amortized cost	750,745
Available for sale debt securities maturities within 1 year fair value	74,921
Available for sale debt securities maturities 1-5 years fair value	252,489
Available for sale debt securities maturities 5-10 years fair value	236,175
Available for sale debt securities maturities after 10 years fair value	176,327
Available for sale debt securities fair value	739,912
Held to maturity debt securities maturities within 1 year amortized cost	2,605
Held to maturity debt securities maturities 1-5 years amortized cost	7,157
Held to maturity debt securities maturities 5-10 years amortized cost	4,414
Held to maturity debt securities maturities after 10 years amortized cost	1,457
Held to maturity securities amortized cost	15,633	$ 20,023
Held to maturity debt securities maturities within 1 year fair value	2,653
Held to maturity debt securities maturities 1-5 years fair value	7,288
Held to maturity debt securities maturities 5-10 years fair value	4,495
Held to maturity debt securities maturities after 10 years fair value	1,484
Held to maturity securities fair value	15,920	20,516
Mortgage-backed securities issued by U.S. government-sponsored agencies and U.S. government-sponsored enterprises [Member]
Schedule of Available for Sale and Held to Maturity Securities [Line Items]
Held to maturity securities amortized cost	15,633	20,023
Held to maturity securities fair value	$ 15,920	$ 20,516