Notes Payable and Other Noncurrent Liabilities (Details) - USD ($) $ in Thousands		3 Months Ended
Jan. 22, 2019	Mar. 31, 2019
Notes Payable and Other Noncurrent Liabilities
Repayments of term loan	$ 59,850
Cash collateral released on repayment of debt	61,667
Amended and restated credit agreement dated January 22, 2019
Notes Payable and Other Noncurrent Liabilities
Amount of credit facilities	$ 325,000
Term of credit facility	5 years
Loan modification costs expensed		$ 150
Amended and restated credit agreement dated January 22, 2019 \| Orbis Education
Notes Payable and Other Noncurrent Liabilities
Acquisition consideration funded by credit agreement	$ 191,000
Amended and restated credit agreement dated January 22, 2019 \| 30 Day LIBOR
Notes Payable and Other Noncurrent Liabilities
Margin on interest rate	2.00%
Amended and restated credit agreement dated January 22, 2019 \| Term loan facility
Notes Payable and Other Noncurrent Liabilities
Amount of credit facilities	$ 243,750
Installment payment as a percentage of principal amount	5.00%
Loan modification costs	$ 1,639
Amended and restated credit agreement dated January 22, 2019 \| Term loan facility \| 30 Day LIBOR
Notes Payable and Other Noncurrent Liabilities
Margin on interest rate		2.00%
Amended and restated credit agreement dated January 22, 2019 \| Revolving Line of Credit [Member]
Notes Payable and Other Noncurrent Liabilities
Amount of credit facilities	81,250
Loan modification costs	596
Amended and restated credit agreement dated January 22, 2019 \| Revolving Line of Credit [Member] \| Orbis Education
Notes Payable and Other Noncurrent Liabilities
Acquisition consideration funded by credit agreement	$ 6,250
Amended and restated credit agreement dated January 22, 2019 \| Revolving Line of Credit [Member] \| 30 Day LIBOR
Notes Payable and Other Noncurrent Liabilities
Margin on interest rate		2.00%

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Percentage points added to the reference rate to compute the variable rate on the debt instrument.

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