Summary of Significant Accounting Policies ASU Adjustment (Details) - USD ($)			12 Months Ended
		Jan. 01, 2019	Dec. 31, 2019	Dec. 31, 2018	Jan. 01, 2018		Dec. 31, 2017	Jan. 01, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Retained Earnings (Accumulated Deficit)			$ 967,587,000	$ 1,165,842,000
Deferred Tax Assets, Net of Valuation Allowance			32,649,000	$ 34,875,000
Right-of-use assets obtained in exchange for new operating lease liabilities			25,360,000
Cumulative effect of accounting change	[1]				$ 0			$ 44,732,000
ASU 2016-09 Cumulative Effect Adjustment for Timing of Recognition of Excess Tax Benefits [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Retained Earnings (Accumulated Deficit)								44,300,000
ASU 2016-09 Cumulative Effect of Actual Forfeiture Rate [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Retained Earnings (Accumulated Deficit)								(700,000)
Additional Paid in Capital								1,100,000
Deferred Tax Assets, Net of Valuation Allowance								$ (400,000)
Accounting Standards Update 2016-02 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Right-of-use assets obtained in exchange for new operating lease liabilities		$ 50,000,000.0
Accounting Standards Update 2018-02 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of accounting change			$ 0		$ 2,969,000	[2]	$ 0

[1] ⁽¹⁾  Please refer to Recently Issued Accounting Standards in Note 1 – Summary of Significant Accounting Policies for additional information.

[2] ⁽¹⁾  Please refer to Recently Issued Accounting Standards in Note 1 – Summary of Significant Accounting Policies and Statements of Stockholders’ Equity for additional information.