Investment Securities Schedule of Held-to-Maturity Securities (Details) - USD ($) $ in Thousands	Sep. 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	7,506	$ 331
Held-to-maturity Securities	389,513	384,324
Securities held to maturity, fair value	396,994	$ 382,341
Due after 1 but within 5 years	1,223
Due after 5 but within 10 years	29,368
Held-to-maturity Securities, Debt Maturities, Year Six Through Ten, Fair Value	30,125
Held-to-maturity Securities, Debt Maturities, Year Two Through Five, Fair Value	1,249
Due after 10 years	6,192
Held-to-maturity Securities, Debt Maturities, after Ten Years, Fair Value	6,268
Held-to-maturity Securities, Debt Maturities, Single Maturity Date, Amortized Cost Basis	36,783
Held-to-maturity Securities, Debt Maturities, Single Maturity Date, Fair Value	37,642
Held-to-maturity Securities, Debt Maturities, without Single Maturity Date, Net Carrying Amount	352,730
Held-to-maturity Securities, Debt Maturities, without Single Maturity Date, Fair Value	359,352
US Government Agencies Residential Mortgage-backed Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity Securities	40,240
Securities held to maturity, fair value	40,619
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity Securities	312,490
Securities held to maturity, fair value	$ 318,733