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Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Fixed maturities available for sale, at amortized cost	$ 18,143,305	$ 16,598,808
Short-term investments available for sale, at amortized cost	1,924,292	957,283
Collateral received under securities lending agreements, at amortized cost	301,089	388,366
Investments accounted for using the fair value option	3,824,796	3,663,477
Securities pledged under securities lending, at amortized cost	294,493	378,738
Allowance for credit losses on premiums receivable	37,781	21,003
Allowance for credit losses on reinsurance recoverable	11,636	1,364
Allowance for credit loss on contractholder receivable	$ 8,638	$ 0
Common shares, par value per share	$ 0.0011	$ 0.0011
Common shares issued (shares)	579,000,841	574,617,195
Common shares held in treasury (shares)	172,280,199	168,997,994
Short-term investments
Short-term investments available for sale, at amortized cost	$ 1,924,292	$ 957,283
Allowance for credit losses on investments	0
Fixed maturities
Allowance for credit losses on investments	$ 2,397

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