RECEIVABLES

Receivables were comprised of the following:



	March 29,		December 31,
(In thousands)	2019		2018
Billed receivables	$	42,147	$	44,868
Unbilled receivables (contract assets)	195,696		181,009
Other	6,273		6,242
Total receivables	$	244,116	$	232,119

As of March 29, 2019 and December 31, 2018, all billed receivables are due from the U.S. government, either directly as prime contractor to the U.S. government or as subcontractor to another prime contractor to the U.S. government. Because our billed receivables are with the U.S. government, we do not believe they represent a material credit risk exposure.

Unbilled receivables are contract assets that represent revenue recognized on long-term contracts in excess of amounts billed as of the balance sheet date. We estimate that approximately $2.3 million of our unbilled receivables as of March 29, 2019 may not be collected within the next 12 months. These amounts relate to the timing of the U.S. government review of indirect rates and contract line item realignments with our customers. Changes in the balance of receivables are primarily due to the timing differences between our performance and customers' payments.