Securities Continuous Unrealized Loss (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	$ 101,817	$ 69,830
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses	2,099	484
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	95,313	81,237
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses	4,664	2,296
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	197,130	151,067
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses	6,763	2,780
US Government and Government Agencies and Authorities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	31,523	14,381
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses	437	99
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	19,838	20,353
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses	1,235	805
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	51,361	34,734
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses	1,672	904
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	55,415	53,440
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses	1,360	363
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	65,608	50,729
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses	2,977	1,276
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	121,023	104,169
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses	4,337	1,639
US States and Political Subdivisions Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	14,879	2,009
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses	302	22
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	9,867	10,155
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses	452	215
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	24,746	12,164
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses	$ 754	$ 237