Investment Securities Number, fair value and gross unrealized holding losses (Details) $ in Thousands	Dec. 31, 2015 USD ($) investment_security	Dec. 31, 2014 USD ($) investment_security
Number
Less than 12 months (in investments) | investment_security	71	42
12 months or Longer (in investments) | investment_security	9	20
Total (in investments) | investment_security	80	62
Fair Value
Less than 12 months	$ 121,775	$ 42,482
12 months or Longer	16,284	25,352
Total	138,059	67,834
Gross Unrealized Holding Losses
Less than 12 months	(923)	(222)
12 months or Longer	(468)	(565)
Total	$ (1,391)	$ (787)
Number
Less than 12 months (in investments) | investment_security	1
12 months or Longer (in investments) | investment_security	0
Total (in investments) | investment_security	1
Fair Value
Less than 12 months	$ 8,330
12 months or Longer	0
Total	8,330
Gross Unrealized Holding Losses
Less than 12 months	(70)
12 months or Longer	0
Total	$ (70)
Total securities
Number, Less than 12 months (in investments) | investment_security	72
Number, 12 months or Longer (in investments) | investment_security	9
Number, Total (in investments) | investment_security	81
Fair Value, Less than 12 months	$ 130,105
Fair Value, 12 months or Longer	16,284
Fair Value, Total	146,389
Gross Unrealized Holding Losses, Less than 12 months	(993)
Gross Unrealized Holding Losses, 12 months or longer	(468)
Gross Unrealized Holding Losses, Total	$ (1,461)
Municipal bonds
Number
Less than 12 months (in investments) | investment_security	32	35
12 months or Longer (in investments) | investment_security	6	16
Total (in investments) | investment_security	38	51
Fair Value
Less than 12 months	$ 15,516	$ 18,129
12 months or Longer	3,349	6,510
Total	18,865	24,639
Gross Unrealized Holding Losses
Less than 12 months	(61)	(117)
12 months or Longer	(36)	(56)
Total	$ (97)	$ (173)
Collateralized mortgage obligation
Number
Less than 12 months (in investments) | investment_security	5
12 months or Longer (in investments) | investment_security	0
Total (in investments) | investment_security	5
Fair Value
Less than 12 months	$ 22,771
12 months or Longer	0
Total	22,771
Gross Unrealized Holding Losses
Less than 12 months	(183)
12 months or Longer	0
Total	$ (183)
Mortgage-backed securities
Number
Less than 12 months (in investments) | investment_security	34	7
12 months or Longer (in investments) | investment_security	3	4
Total (in investments) | investment_security	37	11
Fair Value
Less than 12 months	$ 83,488	$ 24,353
12 months or Longer	12,935	18,842
Total	96,423	43,195
Gross Unrealized Holding Losses
Less than 12 months	(679)	(105)
12 months or Longer	(432)	(509)
Total	$ (1,111)	$ (614)
Number
Less than 12 months (in investments) | investment_security	1
12 months or Longer (in investments) | investment_security	0
Total (in investments) | investment_security	1
Fair Value
Less than 12 months	$ 8,330
12 months or Longer	0
Total	8,330
Gross Unrealized Holding Losses
Less than 12 months	(70)
12 months or Longer	0
Total	$ (70)