Allowance for Loan Losses - Bank's Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended									12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance				$ 10,600				$ 10,150	$ 9,915	$ 10,600	$ 10,150	$ 9,915
Provision for loan losses	$ 1,800	$ 1,231	$ 1,250	400	$ 1,200	$ 570	$ 753	150	235	4,681	2,673	235
Charge-offs										(50)	(2,223)
Recoveries										169
Ending Balance	15,400				10,600					15,400	10,600	10,150
Residential Properties
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance				6,799				6,546	6,135	6,799	6,546	6,135
Provision for loan losses										(130)	253	411
Ending Balance	6,669				6,799					6,669	6,799	6,546
Commercial Real Estate
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance				1,813				1,499	1,425	1,813	1,499	1,425
Provision for loan losses										1,051	624	74
Charge-offs										(50)	(310)
Recoveries										169
Ending Balance	2,983				1,813					2,983	1,813	1,499
Land and Construction
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance				103				67	37	103	67	37
Provision for loan losses										130	36	30
Ending Balance	233				103					233	103	67
Commercial and Industrial Loans
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance				1,649				1,897	2,149	1,649	1,897	2,149
Provision for loan losses										3,578	1,665	(252)
Charge-offs											(1,913)
Ending Balance	5,227				1,649					5,227	1,649	1,897
Consumer Loans
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance				$ 236				$ 141	$ 169	236	141	169
Provision for loan losses										52	95	(28)
Ending Balance	$ 288				$ 236					$ 288	$ 236	$ 141