Investment Securities - (Summary of Held-to-Maturity Securities, Unrealized Losses) (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Schedule of Held-to-maturity Securities [Line Items]
Fair Value, Less than 12 months	$ 49,373	$ 54,791
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(470)	(591)
Fair Value, 12 months or more	29,244	32,146
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(895)	(1,042)
Total Fair Value	78,617	86,937
Held-to-maturity Securities, Continuous Unrealized Loss Position, Accumulated Loss	(1,365)	(1,633)
Residential Mortgage Pass-Through Securities Issued or Guaranteed by U.S. Government Agencies or Sponsored Enterprises [Member]
Schedule of Held-to-maturity Securities [Line Items]
Fair Value, Less than 12 months	25,512	27,799
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(164)	(234)
Total Fair Value	25,512	27,799
Held-to-maturity Securities, Continuous Unrealized Loss Position, Accumulated Loss	(164)	(234)
Other Residential MBS Issued or Guaranteed by U.S. Government Agencies or Sponsored Enterprises [Member]
Schedule of Held-to-maturity Securities [Line Items]
Fair Value, Less than 12 months	23,861	26,992
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(306)	(357)
Fair Value, 12 months or more	29,244	32,146
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(895)	(1,042)
Total Fair Value	53,105	59,138
Held-to-maturity Securities, Continuous Unrealized Loss Position, Accumulated Loss	$ (1,201)	$ (1,399)