Wire Transaction Recovery (Details) - USD ($) $ in Thousands		3 Months Ended				9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2014	Sep. 30, 2014	Sep. 30, 2017	Sep. 30, 2016
Unusual or Infrequent Items, or Both [Abstract]
Description of wire transaction loss					In September 2014, the Company was the victim of a crime involving the transfer of $4.8 million to an overseas account.
Wire transaction loss and related expenses				$ 900	$ 4,900
Wire transaction recovery	[1]	$ 4,770	$ 0			$ 4,770	$ 0

[1] Operating costs and expenses for the three and nine months ended September 30, 2017 reflect probable insurance recovery of amounts associated with the previously reported 2014 wire transaction loss. For additional details, see Note 2, "Wire Transaction Recovery."