Loans Payable - Additional Information (Detail) € in Millions		3 Months Ended			6 Months Ended		12 Months Ended
	Dec. 24, 2014 USD ($) financial_institution	Jun. 30, 2016 USD ($)	Jun. 30, 2016 EUR (€)	Jun. 30, 2015 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2015 USD ($)	Dec. 31, 2015 USD ($)	Aug. 05, 2016 USD ($)
Line of Credit Facility [Line Items]
Interest expense		$ 5,400,000		$ 4,800,000	$ 10,800,000	$ 8,800,000
Currency translation adjustment		(4,542,000)		$ 3,299,000	6,053,000	$ (12,587,000)
Loans payable		614,030,000			$ 614,030,000		$ 600,250,000
Line of Credit | EGL Revolving Credit Facility
Line of Credit Facility [Line Items]
Facility term (years)					5 years
Maximum borrowing capacity		665,000,000			$ 665,000,000
Line of credit facility, remaining borrowing capacity		115,200,000			115,200,000
Proceeds from line of credit | €			€ 75.0
Currency translation adjustment		2,100,000			$ 2,100,000
Line of Credit | EGL Revolving Credit Facility | Subsequent Event
Line of Credit Facility [Line Items]
Optional additional borrowing capacity								$ 166,250,000.00
Line of Credit | Sussex Facility
Line of Credit Facility [Line Items]
Facility term (years)	4 years				4 years
Proceeds from line of credit	$ 109,000,000
Number of financial institutions | financial_institution	2
Percentage of consideration payable for acquisition	50.00%
Repayment of outstanding principal balance					$ 30,500,000		$ 15,000,000
Loans payable		$ 63,500,000			$ 63,500,000