Summary of Significant Accounting Policies (Restricted Cash) (Details) - USD ($) $ in Thousands |
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|---|---|---|---|
| Accounting Policies [Abstract] | |||
| Cash and cash equivalents | $ 22,704 | $ 16,418 | $ 168,214 |
| Restricted cash | 24,078 | 8,007 | 1,656 |
| Total cash, cash equivalents and restricted cash reported in the consolidated statement of cash flows | $ 46,782 | $ 24,425 | $ 169,870 |