Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax [Line Items]
Provision for (benefit from) income taxes	$ 2,788	$ 3,221	$ 2,214	$ 2,982	$ 2,089	$ 2,601	$ 2,124	$ 1,841	$ 11,205	$ 8,655	$ (21,631)
Valuation allowance	3,688				3,303				3,688	3,303
Increase in valuation allowance									400
Undistributed earnings of foreign subsidiaries	11,000				8,700				11,000	8,700
Unrecognized tax benefits that would impact effective tax rate	2,400				2,100				2,400	$ 2,100	$ 2,100
Federal [Member]
Income Tax [Line Items]
Operating loss carryforwards	31,500								31,500
Operating loss carryforwards, excess tax benefits	29,000								29,000
Research and development tax credit	700
Federal [Member] | Research and Development Credits [Member]
Income Tax [Line Items]
Tax credit carryforward	7,000								7,000
State [Member]
Income Tax [Line Items]
Operating loss carryforwards	4,600								4,600
Research and development tax credit									600
State [Member] | Research and Development Credits [Member]
Income Tax [Line Items]
Tax credit carryforward	$ 6,700								$ 6,700
Federal and State Jurisdictions [Member]
Income Tax [Line Items]
Provision for (benefit from) income taxes					$ (23,700)