Liquidity and Capital Resources (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Liquidity and Capital Resources [Abstract]
Cash and cash equivalents	$ 34,391	$ 28,486	$ 46,582	$ 44,078
Total current assets	126,538	96,310
Total current liabilities	50,732	26,777
Net working capital	75,806
Net cash flows from operating activities	$ 25,828	$ 18,807	$ 16,802