Stock-Based Compensation Stock Options (Tables)

6 Months Ended

Sep. 30, 2017

Share-based Compensation Arrangement by Share-based Payment Award

Schedule of Compensation Cost for Share-based Payment Arrangements, Allocation of Share-based Compensation Costs by Plan [Table Text Block]

	Three Months Ended September 30,				Six Months Ended September 30,
	2017		2016		2017		2016
Stock options	$	1,921	$	2,042	$	4,146	$	4,284
Restricted stock and restricted stock units	13,509		12,741		30,088		27,314
Employee stock purchase plan	96		116		393		417
Affiliate management equity plans	776		435		1,552		19,934
Non-employee director awards	1,075		1,150		1,075		1,150
Performance share units	1,078		1,019		2,263		1,869
Employee stock trust	8		7		14		13
Total stock-based compensation expense	$	18,463	$	17,510	$	39,531	$	54,981

Share-based Compensation Arrangements by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding [Table Text Block]

	Six Months Ended September 30,
	2017				2016
	Number of Shares		Weighted-Average Exercise Price Per Share		Number of Shares		Weighted-Average Exercise Price Per Share
Options outstanding at March 31	4,593		$	38.15	4,506		$	38.48
Granted	421		37.64		753		31.31
Exercised	(326	)	29.04		(109	)	28.31
Canceled/forfeited	(70	)	46.08		(319	)	36.42
Options outstanding at September 30	4,618		$	38.63	4,831		$	37.73

Management [Member]

Share-based Compensation Arrangement by Share-based Payment Award

Assumptions used to determine the weighted-average fair value of option grants

	Six Months Ended September 30,
	2017		2016
Expected dividend yield	1.70	%	1.45	%
Risk-free interest rate	1.89	%	1.25	%
Expected volatility	26.79	%	30.95	%
Expected life (in years)	5.09		5.02

Key Employees [Member]

Share-based Compensation Arrangement by Share-based Payment Award

Assumptions used to determine the weighted-average fair value of option grants

	2017		2016
Expected dividend yield	2.96	%	2.87	%
Risk-free interest rate	1.47	%	0.89	%
Expected volatility	27.73	%	26.01	%