CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 7,210	$ 6,741
Other comprehensive income:
Foreign currency translation adjustment	1,743	1,038
Other comprehensive income	1,743	1,038
Comprehensive income	8,953	7,779
Less: Comprehensive income attributable to noncontrolling interest	8	4
Comprehensive income attributable to limited partners	$ 8,945	$ 7,775