Line of Credit (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Mar. 31, 2017	Jan. 04, 2016
Line of Credit Facility [Line Items]
Document Period End Date			Sep. 30, 2017
Loans outstanding	$ 55,000		$ 55,000		$ 15,000
Remaining borrowing capacity	195,000		195,000
Interest expense	520	$ 740	927	$ 1,272
Amortization of debt issuance costs	$ 269	$ 269	$ 538	$ 538
Line of Credit [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity						$ 250,000
Letter of Credit [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity						10,000
Swing-Line Loans [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity						$ 10,000