Investment Securities Schedule of Held-to-Maturity Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Schedule of Held-to-maturity Securities [Line Items]
Due within 1 year	$ 0
Held-to-maturity Securities, Debt Maturities, Next Twelve Months, Fair Value	0
Held-to-maturity Securities, Accumulated Unrecognized Holding Gain	8,794	$ 331
Held-to-maturity Securities	405,976	384,324
Securities held to maturity, fair value	414,770	$ 382,341
Due after 1 but within 5 years	1,231
Due after 5 but within 10 years	28,052
Held-to-maturity Securities, Debt Maturities, Year Six Through Ten, Fair Value	28,940
Held-to-maturity Securities, Debt Maturities, Year Two Through Five, Fair Value	1,265
Due after 10 years	6,525
Held-to-maturity Securities, Debt Maturities, after Ten Years, Fair Value	6,642
Held-to-maturity Securities, Debt Maturities, Single Maturity Date, Amortized Cost Basis	35,808
Held-to-maturity Securities, Debt Maturities, Single Maturity Date, Fair Value	36,847
Held-to-maturity Securities, Debt Maturities, without Single Maturity Date, Net Carrying Amount	370,168
Held-to-maturity Securities, Debt Maturities, without Single Maturity Date, Fair Value	377,923
US Government Agencies Residential Mortgage-backed Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity Securities	41,241
Securities held to maturity, fair value	41,790
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity Securities	328,927
Securities held to maturity, fair value	$ 336,133