Segment Information (Schedule of Segment Perfomance Measures by Segment) (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2013
Segment Reporting Information [Line Items]
Net sales	$ 146,587	$ 145,796	$ 123,765	$ 130,803	$ 139,580	$ 124,830	$ 116,508	$ 129,261	$ 546,951	$ 510,179	$ 499,690
Gross profit	$ 41,166	$ 36,598	$ 30,019	$ 27,651	$ 29,022	$ 24,963	$ 26,984	$ 33,734	135,434	114,703	98,271
Income before income taxes									53,865	44,674	34,550
Operating Segments | Human Health
Segment Reporting Information [Line Items]
Net sales									225,263	160,217	129,667
Gross profit									75,749	48,496	39,306
Income before income taxes									35,152	19,710	17,276
Operating Segments | Pharmaceutical Ingredients
Segment Reporting Information [Line Items]
Net sales									149,296	176,425	184,852
Gross profit									26,683	36,615	31,367
Income before income taxes									8,697	17,557	13,294
Operating Segments | Performance Chemicals
Segment Reporting Information [Line Items]
Net sales									172,392	173,537	185,171
Gross profit									33,002	29,592	27,598
Income before income taxes									$ 14,289	$ 13,273	$ 10,400
Unallocated Corporate
Segment Reporting Information [Line Items]
Net sales
Gross profit
Income before income taxes									$ (4,273)	$ (5,866)	$ (6,420)