Three Months Ended

Six Months Ended

June 30,

(in thousands)

2020

2019

2020

2019

Balance, beginning of period

$

114,038

$

102,879

$

118,211

$

105,837

Billings, excluding billings for customer arrangements with termination rights

53,047

49,477

93,838

89,800

Additions to unearned revenue upon expiration of termination rights

4,599

5,062

9,244

10,062

Recognition of revenue, net of change in unbilled accounts receivable*

(58,746)

(51,019)

(108,355)

(99,300)

Acquired unearned revenue

275

—

275

—

Balance, end of period

$

113,213

$

106,399

$

113,213

$

106,399

* Reconciliation to Revenue Reported per Condensed Consolidated Statement of Operations:

Three Months Ended

Six Months Ended

June 30,

(in thousands)

2020

2019

2020

2019

Revenue billed as of the end of period

$

58,746

$

51,019

$

108,355

$

99,300

Increase (decrease) in total unbilled accounts receivable

179

(154)

268

(353)

Revenue Reported in Condensed Consolidated Statement of Operations

$

58,925

$

50,865

$

108,623

$

98,947