Significant Accounting Policies (Tables)

3 Months Ended

Mar. 31, 2018

Significant Accounting Policies [Abstract]

Schedule of cash, cash equivalents, and restricted cash

The following table illustrates the reconciliation of cash, cash equivalents, and restricted cash shown in the unaudited condensed consolidated statements of cash flows as of March 31, 2017 and 2018 (in thousands):

	For the three months ended
	March 31,
	2017		2018
Cash and cash equivalents	$	147,099	$	165,867
Restricted cash included in other current assets		—		8
Restricted cash included in other long-term assets		500		500
Total cash, cash equivalents, and restricted cash shown in the statement of cash flows	$	147,599	$	166,375

Schedule of tuition receivable and allowance for doubtful accounts

	December 31, 2017		March 31, 2018
Tuition receivable	$	35,809	$	38,772
Allowance for doubtful accounts		(12,687)		(13,775)
Tuition receivable, net	$	23,122	$	24,997

Schedule of allowance for doubtful accounts

	For the three months ended
	March 31,
	2017		2018
Allowance for doubtful accounts, beginning of period	$	10,201	$	12,687
Additions charged to expense		4,382		6,391
Write-offs, net of recoveries		(3,763)		(5,303)
Allowance for doubtful accounts, end of period	$	10,820	$	13,775

Schedule of reconciliation of shares used to calculate basic and diluted earnings per share

	For the three months ended
	March 31,
	2017	2018
Weighted average shares outstanding used to compute basic earnings per share	10,630	10,745
Incremental shares issuable upon the assumed exercise of stock options	35	45
Unvested restricted stock and restricted stock units	456	521
Shares used to compute diluted earnings per share	11,121	11,311