Long-Term Debt and Capital Lease Obligations - Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Debt Instrument [Line Items]
Amortization of deferred debt issuance costs			$ 290	$ 391
Total interest expense	$ 1,816	$ 1,738	5,400	3,940
2.50% Convertible Notes
Debt Instrument [Line Items]
Interest expense at 2.50% coupon rate	725	725	2,166	1,449
Amortization of debt discount	995	921	2,940	1,843
Amortization of deferred debt issuance costs	96	92	290	193
Total interest expense	$ 1,816	$ 1,738	5,396	3,485
Other Borrowings
Debt Instrument [Line Items]
Total interest expense			$ 4	$ 455