Income Taxes - Provision for income taxes charged to operations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Current tax expense	$ 2,067	$ 2,606	$ 1,160
Deferred tax expense	746	109	1,181
Total income tax expense	$ 2,813	$ 2,715	$ 2,341