FOREIGN OPERATIONS: (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Financial information by geographic area
Revenues	$ 224,655	$ 221,193	$ 207,345	$ 196,895	$ 205,734	$ 208,246	$ 204,248	$ 186,683	$ 850,088	$ 804,911	$ 805,153
Long-lived assets excluding financial instruments	773,839				782,683				773,839	782,683
United States
Financial information by geographic area
Revenues									770,043	709,133	692,773
Long-lived assets excluding financial instruments	748,123				749,591				748,123	749,591
Foreign
Financial information by geographic area
Revenues									80,045	95,778	112,380
Long-lived assets excluding financial instruments	25,716				33,092				25,716	33,092
Europe
Financial information by geographic area
Revenues									52,562	59,958	73,294
Long-lived assets excluding financial instruments	11,899				11,466				11,899	11,466
APAC
Financial information by geographic area
Revenues									25,138	32,658	34,540
Long-lived assets excluding financial instruments	$ 13,817				20,682				13,817	20,682
Other
Financial information by geographic area
Revenues									$ 2,345	3,162	$ 4,546
Long-lived assets excluding financial instruments					$ 944					$ 944