Stockholders' Equity - Stock Appreciation Rights (Details) - Stock Appreciation Rights (SARs) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Maximum contractual term of SARs with final vesting date of December 31, 2011 (in years)	10 years
Maximum contractual term of SARs with final vesting date of December 31, 2016 (in years)	15 years
Stock Incentive Plan 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock appreciation rights issued	0	0	0	0
Equity Incentive Plans 2006
Number of Shares
Nonvested at the beginning of the period (in shares)	620,000	715,000	730,000
Exercised (in shares)	(290,000)	(80,000)	(15,000)
Forfeited (in shares)	(90,000)	(15,000)
Nonvested at the end of the period (in shares)	240,000	620,000	715,000	730,000
Weighted- Average Exercise Price
Outstanding at the beginning of the period (in dollars per share)	$ 26.73	$ 26.73	$ 26.73
Exercised (in dollars per share)	26.73	26.73	26.73
Forfeited (in dollars per share)	26.73	26.73
Outstanding at the end of the period (in dollars per share)	$ 26.73	$ 26.73	$ 26.73	$ 26.73
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Weighted- Average Remaining Contractual Term (Years)	5 years 1 month 10 days	3 years 6 months	5 years 9 months 18 days	6 years 8 months 12 days
Aggregate Intrinsic Value	$ 7,920	$ 20,600	$ 33,000	$ 38,700
Exercisable (in shares)	240,000
Exercisable (in dollars per share)	$ 26.73
Exercisable (in years)	5 years 1 month 10 days
Exercisable (in dollars)	$ 7,920