Summary of Significant Accounting Policies - Additional Information (Details) - USD ($) shares in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Mar. 31, 2017	Dec. 13, 2016
Net Investment Income [Line Items]
Held-to-maturity short-term investments	$ 0	$ 0	$ 0	$ 0	$ 19,931,000
Depreciation expense	$ 1,280,000	$ 1,290,000	$ 2,565,000	$ 2,647,000
Effective antidilutive securities excluded from computation of net income per share (in shares)	553	508	553	508
Commercial Paper [Member]
Net Investment Income [Line Items]
Held-to-maturity short-term investments					19,931,000
The McCall Pattern Company [Member]
Net Investment Income [Line Items]
Step up to fair value of inventory acquired						$ 21,773,000
Remaining amount of inventory acquired	$ 11,295,000		$ 11,295,000		$ 18,187,000