Line of Credit - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Mar. 31, 2017	Jan. 04, 2016
Line Of Credit Facility [Line Items]
Line of credit	$ 39,000,000		$ 39,000,000		$ 15,000,000
Remaining borrowing capacity	211,000,000		211,000,000
Interest expense	463,000	$ 359,000	1,390,000	$ 1,631,000
Amortization of debt issuance costs	$ 269,000	$ 269,000	$ 807,000	$ 807,000
Revolving Credit Facility
Line Of Credit Facility [Line Items]
Maximum borrowing capacity						$ 250,000,000
Credit agreement maturity date			Jan. 04, 2021
Letter of Credit [Member]
Line Of Credit Facility [Line Items]
Maximum borrowing capacity						10,000,000
Swing-Line Loans [Member]
Line Of Credit Facility [Line Items]
Maximum borrowing capacity						$ 10,000,000