Income Taxes - Significant Components of The Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Deferred tax assets
Accruals and prepaids	$ 18,010	$ 12,904
Deferred revenue	23,559	34,710
Net operating loss carryforwards	218,719	229,464
Stock-based compensation	6,908	3,748
Investment tax and other credits	18,454	11,261
Total deferred tax assets	285,650	292,087
Less: Valuation allowance	(663)
Gross deferred tax assets	284,987	292,087
Deferred tax liabilities
Capitalized initial direct costs	45,030	27,539
Fixed asset depreciation	206,754	178,511
Deferred tax on investment in partnerships	448,600	276,183
Gross deferred tax liabilities	700,384	482,233
Net deferred tax liabilities	$ (415,397)	$ (190,146)