Summary of Significant Accounting Policies - ASU Adoption (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease right-of-use assets	$ 16,964	$ 22,000	$ 0
Lease liabilities	23,948	28,600
ASU 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accrued rent		7,200
Prepaid rent		$ 600
Prepaid Expenses
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Capitalized implementation costs	100
Other Noncurrent Assets
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Capitalized implementation costs	$ 800