Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Schedule Of Income Taxes [Line Items]
Statutory tax rate	35.00%	35.00%	35.00%
Valuation allowance related to gross deferred tax assets	$ 3,114	$ 2,670
Deferred tax assets operating loss carry forwards, total	31,200
Unrecognized tax benefits, accrued interest	$ 100	$ 100	$ 100
Minimum
Schedule Of Income Taxes [Line Items]
Deferred tax assets operating loss carry forwards, expiration date	2020
Maximum
Schedule Of Income Taxes [Line Items]
Deferred tax assets operating loss carry forwards, expiration date	2036
PENNSYLVANIA
Schedule Of Income Taxes [Line Items]
Valuation allowance related to gross deferred tax assets	$ 3,100