Long-Term Debt (Narrative - United Kingdom) (Details) £ in Thousands, $ in Thousands	6 Months Ended
	Jun. 30, 2016 GBP (£)	Jun. 30, 2016 USD ($)	Dec. 31, 2015 USD ($)
Line of Credit Facility [Line Items]
Line of Credit Facility, Amount Outstanding		$ 165,270	$ 165,000
NatWest Bank [Member] | Base Rate [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.50%
NatWest Bank [Member] | Foreign Line of Credit [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	£ 1,500	1,997
Line of Credit Facility, Collateral	This credit facility supports the subsidiary's working capital requirements and is collateralized by substantially all of the assets of its United Kingdom operations.
Line of Credit Facility, Interest Rate Description	. The interest rate on this facility is the financial institution's base rate plus 1.50%.
Line of Credit Facility, Amount Outstanding		0
Line of Credit Facility, Current Borrowing Capacity		1,645
NatWest Bank Outstanding Guarantees [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Amount Outstanding		352
NatWest Bank Outstanding Guarantees [Member] | Foreign Line of Credit [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Amount Outstanding		$ 352