Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Contingency [Line Items]
Investment Tax Credit	$ 9,300	$ 4,200
Tax Credit Carryforward, Expiration Date	2028
Tax benefit realized upon settlement	50.00%
Unrecognized Tax Benefits	$ 1,500	1,525	$ 0
Unrecognized Tax Benefits Income Tax Penalties And Interest Accrued	300	300
State
Income Tax Contingency [Line Items]
Net operating loss carryforwards	$ 524,900
Net operating loss carryforwards, Year of expiration	2024
Federal
Income Tax Contingency [Line Items]
Net operating loss carryforwards	$ 571,300	595,000
Net operating loss carryforwards, Year of expiration	2028
California
Income Tax Contingency [Line Items]
Net operating loss carryforwards	$ 348,200	368,000
Net operating loss carryforwards, Year of expiration	2028
Other State
Income Tax Contingency [Line Items]
Net operating loss carryforwards	$ 176,700	178,600
Net operating loss carryforwards, Year of expiration	2024
California Enterprise Zone Credits.
Income Tax Contingency [Line Items]
Investment Tax Credit	$ 1,000	1,000
Windfall Stock Option | Federal
Income Tax Contingency [Line Items]
Net operating loss carryforwards	8,600	5,300
Windfall Stock Option | California
Income Tax Contingency [Line Items]
Net operating loss carryforwards	4,500	1,300
Windfall Stock Option | Other State
Income Tax Contingency [Line Items]
Net operating loss carryforwards	$ 2,400	$ 2,500