v3.26.1
Reinsurance - Narrative (Details) - USD ($)
$ in Millions
Jun. 30, 2026
Dec. 31, 2025
Insurance [Abstract]
Loss reserve balance
$ 92.1
$ 72.3
X
- Definition
Loss Reserve, Net
+ References
No definition available.
+ Details
Name:
nni_LossReserveNet
Namespace Prefix:
nni_
Data Type:
xbrli:monetaryItemType
Balance Type:
credit
Period Type:
instant
X
- References
No definition available.
+ Details
Name:
us-gaap_InsuranceAbstract
Namespace Prefix:
us-gaap_
Data Type:
xbrli:stringItemType
Balance Type:
na
Period Type:
duration