v3.19.3.a.u2

Summary of Significant Accounting Policies - Components of Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
AOCI Attributable to Parent, Net of Tax [Roll Forward] |  |  |
Balance at beginning of period | $ 1,530,241 | $ (551,365) | $ (334,810)
Other comprehensive loss | 3,124 | (163) | (754)
Balance at end of period | 1,174,810 | 1,530,241 | (551,365)
Unrealized Gain (Loss) on Available-for-Sale Debt Securities |  |  |
AOCI Attributable to Parent, Net of Tax [Roll Forward] |  |  |
Balance at beginning of period | (1,320) | (1,157) |
Other comprehensive loss | 3,124 | (163) |
Balance at end of period | $ 1,804 | $ (1,320) | $ (1,157)

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