Investments - Schedule of Contractual Maturities of Available-for-Sale and Held-to-Maturity Securities (Details) $ in Thousands	Jun. 30, 2020 USD ($)
Available-for-sale, Amortized Cost
Within 1 year	$ 239,195
After 1 year through 5 years	104,331
Amortized Cost	343,526
Available-for-sale, Estimated Fair Value
Within 1 year	240,864
After 1 year through 5 years	106,146
Total	347,010
Held-to-maturity, Amortized Cost
Within 1 year	1,820
After 1 year through 5 years	1,668
Total	3,488
Held-to-maturity, Estimated Fair Value
Within 1 year	1,820
After 1 year through 5 years	1,764
Total	$ 3,584