SEGMENT INFORMATION (Details) (USD $)	3 Months Ended		6 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Mar. 31, 2012
Segment Reporting Information [Line Items]
Total segment gross revenue	$ 365,754,000	$ 330,992,000	$ 728,362,000	$ 652,097,000
Total intrasegment gross revenue	647,000	677,000	1,026,000	684,000
Total consolidated gross revenue	365,754,000	330,992,000	728,362,000	652,097,000
Total earnings from unconsolidated affiliates, net of losses - equity method investments	6,994,000	(4,037,000)	8,983,000	1,956,000
Total consolidated operating income	47,328,000	9,595,000	87,321,000	46,000,000
Total depreciation and amortization	23,321,000	25,431,000	44,693,000	48,139,000
Total identifiable assets	2,785,468,000		2,785,468,000		2,740,363,000
Total investments in unconsolidated affiliates - equity method	207,786,000		207,786,000		198,710,000
Construction in progress within property and equipment	121,200,000		121,200,000		126,600,000
Gain Loss On Disposition Of Other Assets [Member]
Segment Reporting Information [Line Items]
Total consolidated operating income	(1,262,000)	(1,611,000)	(6,577,000)	(195,000)
Corporate And Other [Member]
Segment Reporting Information [Line Items]
Total segment gross revenue	9,127,000	9,443,000	16,637,000	16,832,000
Total intrasegment gross revenue	591,000	120,000	711,000	(324,000)
Total consolidated gross revenue	9,718,000	9,563,000	17,348,000	16,508,000
Total earnings from unconsolidated affiliates, net of losses - equity method investments	0	7,000	0	7,000
Total consolidated operating income	(15,161,000)	(33,736,000)	(28,231,000)	(51,245,000)
Total depreciation and amortization	915,000	1,339,000	1,799,000	2,098,000
Total identifiable assets	458,517,000		458,517,000		410,157,000
Total investments in unconsolidated affiliates - equity method	9,532,000		9,532,000		2,378,000
Intersegment Elimination [Member]
Segment Reporting Information [Line Items]
Total consolidated gross revenue	(647,000)	(677,000)	(1,026,000)	(684,000)
Europe [Member]
Segment Reporting Information [Line Items]
Total segment gross revenue	154,111,000	140,244,000	308,068,000	274,524,000
Total intrasegment gross revenue	2,000	(23,000)	65,000	235,000
Total consolidated gross revenue	154,113,000	140,221,000	308,133,000	274,759,000
Total earnings from unconsolidated affiliates, net of losses - equity method investments	2,368,000	2,466,000	4,374,000	5,324,000
Total consolidated operating income	27,008,000	23,586,000	48,884,000	46,835,000
Total depreciation and amortization	8,444,000	8,015,000	16,008,000	15,922,000
Total identifiable assets	862,758,000		862,758,000		779,160,000
Total investments in unconsolidated affiliates - equity method	9,452,000		9,452,000		11,410,000
West Africa [Member]
Segment Reporting Information [Line Items]
Total segment gross revenue	68,217,000	64,041,000	138,671,000	118,548,000
Total intrasegment gross revenue	0	0	0	0
Total consolidated gross revenue	68,217,000	64,041,000	138,671,000	118,548,000
Total consolidated operating income	13,430,000	16,120,000	29,561,000	27,351,000
Total depreciation and amortization	3,051,000	3,244,000	6,193,000	6,514,000
Total identifiable assets	383,879,000		383,879,000		376,903,000
North America [Member]
Segment Reporting Information [Line Items]
Total segment gross revenue	57,321,000	47,794,000	110,031,000	91,961,000
Total intrasegment gross revenue	54,000	463,000	250,000	538,000
Total consolidated gross revenue	57,375,000	48,257,000	110,281,000	92,499,000
Total consolidated operating income	6,130,000	2,571,000	12,605,000	4,155,000
Total depreciation and amortization	3,107,000	5,947,000	6,373,000	9,634,000
Total identifiable assets	315,987,000		315,987,000		276,074,000
Australia [Member]
Segment Reporting Information [Line Items]
Total segment gross revenue	44,839,000	33,323,000	89,341,000	78,618,000
Total intrasegment gross revenue	0	117,000	0	235,000
Total consolidated gross revenue	44,839,000	33,440,000	89,341,000	78,853,000
Total consolidated operating income	6,829,000	576,000	13,338,000	5,100,000
Total depreciation and amortization	2,504,000	2,816,000	4,987,000	5,938,000
Total identifiable assets	212,824,000		212,824,000		295,895,000
Other International [Member]
Segment Reporting Information [Line Items]
Total segment gross revenue	32,139,000	36,147,000	65,614,000	71,614,000
Total intrasegment gross revenue	0	0	0	0
Total consolidated gross revenue	32,139,000	36,147,000	65,614,000	71,614,000
Total earnings from unconsolidated affiliates, net of losses - equity method investments	4,626,000	(6,510,000)	4,609,000	(3,375,000)
Total consolidated operating income	10,354,000	2,089,000	17,741,000	13,999,000
Total depreciation and amortization	5,300,000	4,070,000	9,333,000	8,033,000
Total identifiable assets	551,503,000		551,503,000		602,174,000
Total investments in unconsolidated affiliates - equity method	$ 188,802,000		$ 188,802,000		$ 184,922,000