Fair Value Measurements (Narrative) (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2016 USD ($) $ / derivatives	Dec. 31, 2015 USD ($)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Net asset value required to be maintained by money market funds (in dollars per unit) | $ / derivatives	1.00
Minimum
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Discount rate range (percent)	3.00%
Maximum
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Discount rate range (percent)	22.00%
Restricted cash and cash equivalents
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Available-for-sale securities, amortized cost	$ 40,488	$ 51,142
Paladin Labs Inc.
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Joint venture investments	$ 9,100