Investments Maturities of AFS Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Debt Maturities, Next Twelve Months, Amortized Cost Basis	$ 90,599
Available-for-sale Securities, Debt Maturities, Year Two Through Five, Amortized Cost Basis	310,027
Available-for-sale Securities, Debt Maturities, Year Six Through Ten, Amortized Cost Basis	243,664
Available-for-sale Securities, Debt Maturities, after Ten Years, Amortized Cost Basis	521,616
Investment securities available for sale at amortized cost	1,165,906	$ 1,084,105
Available-for-sale Securities, Debt Maturities, Next Twelve Months, Fair Value	91,045
Available-for-sale Securities, Debt Maturities, Year Two Through Five, Fair Value	316,819
Available-for-sale Securities, Debt Maturities, Year Six Through Ten, Fair Value	250,725
Available-for-sale Securities, Debt Maturities, after Ten Years, Fair Value	532,934
Available-for-sale Securities	$ 1,191,523	$ 1,084,510