Capital Stock (Stock Appreciation Rights) (Details) (USD $) In Thousands, except Share data, unless otherwise specified						9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended	9 Months Ended
	Dec. 31, 2012	Mar. 31, 2012	Jun. 30, 2011	Dec. 31, 2012 Stock Appreciation Rights (SARs) [Member]	Mar. 31, 2012 Stock Appreciation Rights (SARs) [Member]	Dec. 31, 2012 Grant Date February 5, 2009 [Member] Stock Appreciation Rights (SARs) [Member]	Mar. 31, 2012 Grant Date February 5, 2009 [Member] Stock Appreciation Rights (SARs) [Member]	Dec. 31, 2012 Grant Date April 6, 2009 [Member] Stock Appreciation Rights (SARs) [Member]	Mar. 31, 2012 Grant Date April 6, 2009 [Member] Stock Appreciation Rights (SARs) [Member]	Dec. 31, 2012 Grant Date March 17, 2010 [Member] Stock Appreciation Rights (SARs) [Member]	Dec. 31, 2012 Grant Date January 19, 2012 [Member] Stock Appreciation Rights (SARs) [Member]	Dec. 31, 2012 Grant Date February 9, 2012 [Member] Stock Appreciation Rights (SARs) [Member]	Dec. 31, 2012 Grant Dates July 18, 2008 and February 15, 2011[Member] [Domain] Stock Appreciation Rights (SARs) [Member]
Authorized common shares	500,000,000	500,000,000	500,000,000
SARs Outstanding						150,000		75,000		500,000	2,400,000	350,000
Vested and Exercisable						150,000		75,000		500,000	0	0
Exercise Price (in dollars per share)						$ 5.45		$ 5.17		$ 5.95	$ 9.48	$ 11.01
Original Vesting Period (in years)						3 years		4 years		4 years	3 years	3 years
Fair Value (in dollars per share)						$ 10.97		$ 11.26		$ 10.58	$ 8.32	$ 7.44
Liability (in thousands)				$ 14,900	$ 32,400	$ 1,646		$ 844		$ 5,291	$ 6,328	$ 776
SARs exercised							700,000		625,000				1,750,000