European Non-Controlling Redeemable Equity - Summary of Redeemable Noncontrolling Interests (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Redeemable Noncontrolling Interest [Line Items]
Redemption value adjustment				$ 3,625
Dividends accrued	$ 262	$ 511	$ 383	1,084
European non-controlling redeemable equity translation adjustment		$ 2,900		$ 2,900
Redeemable Noncontrolling Interest [Member]
Redeemable Noncontrolling Interest [Line Items]
Beginning balance			13,849
Reclassification of non-controlling interests					$ 51,943
Redemption value adjustment					3,625
Dividends accrued			383		1,512
Dividends paid			(680)		(964)
European non-controlling redeemable equity translation adjustment			(110)		(3,219)
Purchase of shares			(1,411)		(39,048)
Ending Balance	$ 12,031		$ 12,031		$ 13,849