Securities Lending (Details) - USD ($) $ in Thousands		Dec. 31, 2019	Dec. 31, 2018
Securities borrowed
Gross amounts recognized		$ 814,331	$ 931,346
Gross amounts offset in the consolidated balance sheets	[1]
Net amounts included in the consolidated balance sheets		814,331	931,346
Amounts not offset in the consolidated balance sheets but eligible for offsetting upon counterparty default	[2]	814,331	931,346
Net amounts
Securities loaned
Gross amounts recognized		810,495	930,522
Gross amounts offset in the consolidated balance sheets	[1]
Net amounts included in the consolidated balance sheets		810,495	930,522
Amounts not offset in the consolidated balance sheets but eligible for offsetting upon counterparty default	[2]	810,495	930,522
Net amounts

[1] Includes financial instruments subject to enforceable master netting provisions that are permitted to be offset to the extent an event of default has occurred.

[2] Includes the amount of cash collateral held/posted.