CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 461,304	$ 277,766
Accounts receivable and unbilled, net (includes $2.7 million and $2.6 million with related parties at December 31, 2021 and 2020, respectively)	186,432	160,962
Prepaid expenses and other current assets	43,176	34,923
Total current assets	690,912	473,651
Property and equipment, net	93,153	85,017
Operating lease right-of-use assets	129,558	113,809
Goodwill	662,396	662,396
Intangible assets, net	41,360	46,474
Deferred income taxes	25,134	536
Other assets	17,422	8,794
Total assets	1,659,935	1,390,677
Current liabilities:
Accounts payable (includes $0.3 million and $0.2 million with related parties at December 31, 2021 and 2020, respectively)	25,678	26,552
Accrued expenses	159,286	134,367
Advanced billings (includes $8.3 million and $6.5 million with related parties at December 31, 2021 and 2020, respectively)	344,641	255,664
Other current liabilities	27,612	23,527
Total current liabilities	557,217	440,110
Operating lease liabilities	130,965	115,143
Deferred income tax liability	1,080	13,551
Other long-term liabilities	17,745	16,094
Total liabilities	707,007	584,898
Commitments and contingencies (see Note 12)
Shareholders’ equity:
Preferred stock - $0.01 par-value; 5,000,000 shares authorized; no shares issued and outstanding at December 31, 2021 and 2020, respectively	0	0
Common stock - $0.01 par-value; 250,000,000 shares authorized at December 31, 2021 and 2020, respectively; 36,006,778 and 35,519,989 shares issued and outstanding at December 31, 2021 and 2020, respectively	360	355
Treasury stock - 180,000 and 185,000 shares at December 31, 2021 and 2020, respectively	(5,427)	(5,578)
Additional paid-in capital	727,857	695,904
Retained earnings	234,984	115,229
Accumulated other comprehensive loss	(4,846)	(131)
Total shareholders’ equity	952,928	805,779
Total liabilities and shareholders’ equity	$ 1,659,935	$ 1,390,677