Unearned Revenue

12 Months Ended

Dec. 31, 2019

Unearned Revenue

Unearned Revenue

14. Unearned Revenue

Changes in unearned revenue were as follows for the years ended December 31, 2019 and 2018:

	Year ended December 31,
(in thousands)	2019		2018
Balance, beginning of period	$	105,837	$	77,022
Billings, excluding billings for customer arrangements with termination rights		196,351		205,816
Additions to unearned revenue upon expiration of termination rights		20,395		17,651
Recognition of revenue, net of change in unbilled accounts receivable*		(204,372)		(194,652)
Balance, end of period	$	118,211	$	105,837
* Reconciliation to Revenue Reported in Consolidated Statement of Operations:
	Year ended December 31,
(in thousands)	2019		2018
Revenue billed as of the end of period	$	204,372	$	194,652
Increase (decrease) in total unbilled accounts receivable		864		(1,460)
Revenue Reported in Consolidated Statement of Operations	$	205,236	$	193,192

Revenue allocated to remaining performance obligations includes unearned revenue plus contractually committed amounts that will be invoiced and recognized as revenue in future periods, but excludes amounts invoiced and not recognized as revenue under customer arrangements that contain termination rights. Remaining performance obligations were $129.4 million as of December 31, 2019, of which we expect to recognize approximately 72% as revenue over the next 12 months and the remainder thereafter.

As of December 31, 2019 and 2018, the balance of customer arrangements that contain termination rights was $16.1 million and $19.4 million, respectively.