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Unaudited Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Thousands | Sep. 30, 2020 | Dec. 31, 2019
--- | --- | ---
Fixed maturities available for sale, at amortized cost | $ 17,955,515 |  | $ 16,598,808
Allowance for credit losses on investments | 3,933 |  | 0
Short-term investments available for sale, at amortized cost | 2,038,244 |  | 957,283
Collateral received under securities lending, at amortized cost | 64,251 |  | 388,366
Securities pledged under securities lending, at amortized cost | 62,662 |  | 378,738
Allowance for credit losses on premiums receivable | 37,100 |  | 21,003
Allowance for credit losses on reinsurance recoverable | 13,994 |  | 1,364
Allowance for credit losses on contractholder receivable | $ 5,902 |  | $ 0
Common shares, par value per share | $ 0.0011 |  | $ 0.0011
Common shares issued (shares) | 578,024,671 |  | 574,617,195
Common shares held in treasury (shares) | 172,005,713 |  | 168,997,994
Fixed maturities |  |  |
Allowance for credit losses on investments | $ 3,933 |  |
Short-term investments |  |  |
Allowance for credit losses on investments | 0 | [1] | $ 0
Short-term investments available for sale, at amortized cost | $ 2,038,244 |  | $ 957,283
[1] | Effective January 1, 2020, the Company adopted ASU 2016-13 and as a result any credit impairment losses on the Company’s available-for-sale investments are recorded as an allowance, subject to reversal.

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