Business Segments, Concentration of Business, and Credit Risk and Significant Customers (Details 2) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Mar. 31, 2014	Sep. 30, 2013	Mar. 31, 2013
Reconciliations of total assets from reportable segments to the condensed consolidated balance sheets
Total assets for reportable segments	$ 1,402,003	$ 1,064,204
Unallocated cash and cash equivalents	114,651	245,088	84,107	64,591
Consolidated total assets	1,402,003	1,064,204
Reportable segments
Reconciliations of total assets from reportable segments to the condensed consolidated balance sheets
Total assets for reportable segments	1,073,471	654,679
Consolidated total assets	1,073,471	654,679
Unallocated to Segments
Reconciliations of total assets from reportable segments to the condensed consolidated balance sheets
Unallocated cash and cash equivalents	114,651	245,088
Unallocated deferred tax assets	37,298	38,933
Other unallocated corporate assets	$ 176,583	$ 125,504