Accumulated Other Comprehensive Income (Reclassification out of Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTableTextBlock [Line Items]
Unrealized gain on available-for-sale investments	$ (3,193)	$ (170)
Total reclassifications for the period	(3,193)	(170)
Other expense (income), net | Amount Reclassified from Accumulated Other Comprehensive Income
ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTableTextBlock [Line Items]
Unrealized gain on available-for-sale investments	(5,149)	(274)
Income before income taxes | Amount Reclassified from Accumulated Other Comprehensive Income
ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTableTextBlock [Line Items]
Unrealized gain on available-for-sale investments	(5,149)	(274)
Income tax expense | Amount Reclassified from Accumulated Other Comprehensive Income
ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTableTextBlock [Line Items]
Unrealized gain on available-for-sale investments	$ 1,956	$ 104