Income Taxes Schedule of Effective Income Tax Rate Reconciliation (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Income tax reconciliation, income tax expense, at federal statutory income tax rate									$ 11,004	$ 9,341	$ 8,474
Effective income tax rate reconciliation, at federal statutory income tax rate									35.00%	35.00%	35.00%
Income tax reconciliation, state income taxes									$ 957	$ 596	$ 687
Effective income tax rate reconciliation, state income taxes									3.00%	2.20%	2.80%
Income tax reconciliation, tax exempt interest income									$ (1,786)	$ (1,525)	$ (1,331)
Effective income rate tax reconciliation, tax exempt interest income									(5.70%)	(5.70%)	(5.50%)
Income tax reconciliation, nondeductible interest expense to own tax-exempts									$ 43	$ 42	$ 46
Effective income tax rate reconciliation, nondeductible interest expense to own tax-exempts									0.10%	0.20%	0.20%
Income tax reconciliation, tax-exempt increase in cash value of life insurance and gains									$ (254)	$ (256)	$ (226)
Effective income tax rate reconciliation, tax-exempt increase in cash value of life insurance and gains									(0.80%)	(1.00%)	(1.00%)
Income tax reconciliation, capital loss carryforward									$ (130)	$ (1,318)	$ 0
Effective income tax rate reconciliation capital loss carryforward									(0.40%)	(4.90%)	(0.00%)
Income tax reconciliation, low income housing tax credits									$ (275)	$ (160)	$ (79)
Effective income tax rate reconciliation, low income housing tax credits									(0.90%)	(0.60%)	(0.30%)
Income tax reconciliation, new markets tax credits									$ 0	$ 0	$ (273)
Effective income tax rate reconciliation, new markets tax credits									(0.00%)	(0.00%)	(1.10%)
Income tax reconciliation, other adjustments									$ 138	$ (71)	$ 22
Effective income tax rate reconciliation, other adjustments									0.50%	(0.30%)	0.10%
Income tax expense	$ 2,596	$ 2,466	$ 2,361	$ 2,274	$ 147	$ 2,362	$ 2,181	$ 1,959	$ 9,697	$ 6,649	$ 7,320
Effective income tax rate									30.80%	24.90%	30.20%