Investment Securities - Unrealized Loss Position Summary (Details) - U.S. government-sponsored mortgage-backed securities $ in Thousands	Jun. 30, 2016 USD ($) item	Dec. 31, 2015 USD ($) item
Investment Securities
Less Than 12 Months Fair Value	$ 1,421	$ 142,810
Less Than 12 Months Unrealized Losses	1	3,939
12 Months or Longer Fair Value	33,499	53,142
12 Months or Longer Unrealized Losses	$ 245	$ 2,230
Total Number of Securities | item	13	43
Total Fair Value	$ 34,920	$ 195,952
Total Unrealized Losses	$ 246	$ 6,169