Significant Accounting Policies - Components of Net Periodic Pension Cost of Defined Benefit Plan Recognized (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Accounting Policies [Abstract]
Service cost	$ 15	$ 15	$ 46	$ 44
Interest cost	9	9	28	26
Amortization of prior service cost	22	21	63	62
Net periodic benefit cost	$ 46	$ 45	$ 137	$ 132