Balance Sheet Account Detail (Fair Value Measurements) (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	$ 31,448	$ 124,553
Contingently issuable common stock	14,800	14,700
Quoted prices in active markets for identical assets (Level 1) | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	31,448	124,553
Contingently issuable common stock	0	0
Significant other observable inputs (Level 2) | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Contingently issuable common stock	0	0
Fair value of long-term debt	244,200	207,900
Significant unobservable inputs (Level 3) | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Contingently issuable common stock	$ 14,800	$ 14,700