Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2015	Mar. 31, 2015
Statement of Financial Position [Abstract]
Property, Plant and Equipment, Gross	$ 1,064,635	$ 1,053,927
Property and equipment, accumulated depreciation	813,954	804,286
Property, Plant and Equipment, Net	$ 250,681	$ 249,641
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, authorized shares	10,000,000	10,000,000
Preferred stock, issued shares	0	0
Common Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Common stock, authorized shares	175,000,000	175,000,000
Common stock, issued shares	46,508,000	46,508,000
Treasury stock, shares	784,781	1,056,508