PROPERTY AND EQUIPMENT: (Details) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Mar. 31, 2015
Property and Equipment
Property and equipment, gross	$ 505,736		$ 505,721
Less accumulated depreciation and amortization	325,995		329,467
Property and equipment, net	179,741		176,254
Depreciation expense on property and equipment	9,900	$ 9,200
Land
Property and Equipment
Property and equipment, gross	6,737		6,737
Buildings and improvements
Property and Equipment
Property and equipment, gross	218,982		202,439
Data processing equipment
Property and Equipment
Property and equipment, gross	243,741		245,538
Office furniture and other equipment
Property and Equipment
Property and equipment, gross	$ 36,276		$ 51,007