Consolidated Statements of Operations and Comprehensive Income (Unaudited) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended				6 Months Ended		12 Months Ended
	Jun. 30, 2012	Mar. 31, 2012	Jun. 30, 2011	Mar. 31, 2011	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2012
Cost of sales:
Inventory impairments and land option cost write-offs					$ 2.2	$ 22.7
Gross profit:
Loss (gain) on early retirement of debt, net					(0.1)	4.2
Income (loss) before income taxes		42.3		(30.8)	71.5	(50.7)	134.2
Income tax expense (benefit)		1.7		(58.6)	3.2	(58.1)
Net income		40.6		27.8	68.3	7.4
Other comprehensive income (loss), net of income tax:
Unrealized loss related to available-for-sale securities		(0.1)				(0.3)
Comprehensive income		40.5		27.8	68.3	7.1
Basic net income per common share		$ 0.13		$ 0.09	$ 0.22	$ 0.02
Net income per common share assuming dilution		$ 0.13		$ 0.09	$ 0.21	$ 0.02
Cash dividends declared per common share	$ 0.0375	$ 0.0375	$ 0.0375	$ 0.0375	$ 0.075	$ 0.075
Homebuilding [Member]
Revenues:
Home sales		930.6		733.0	1,814.9	1,494.1
Land/lot sales		5.0		0.1	6.3	6.0
Total revenues		935.6		733.1	1,821.2	1,500.1
Cost of sales:
Home sales		767.2		613.9	1,502.7	1,256.4
Land/lot sales		3.2		0.1	3.2	6.0
Inventory impairments and land option cost write-offs		0.8		14.3	2.2	22.7
Total cost of sales		771.2		628.3	1,508.1	1,285.1
Gross profit:
Home sales		163.4		119.1	312.2	237.7
Land/lot sales		1.8			3.1
Inventory impairments and land option cost write-offs		(0.8)		(14.3)	(2.2)	(22.7)
Gross profit		164.4		104.8	313.1	215.0
Selling, general and administrative expense		127.5		123.2	246.5	242.0
Interest expense		5.5		14.7	12.5	31.0
Loss (gain) on early retirement of debt, net				2.7	(0.1)	4.2
Other (income)		(3.2)		(3.4)	(5.5)	(5.6)
Income (loss) before income taxes		34.6		(32.4)	59.7	(56.6)
Financial Services [Member]
Gross profit:
Interest expense		0.8		0.1	1.7	0.4
Income (loss) before income taxes		7.7		1.6	11.8	5.9
Revenues, net of recourse and reinsurance expense		25.6		18.0	46.6	39.2
General and administrative expense		19.6		18.2	38.5	37.1
Interest and other (income)		$ (2.5)		$ (1.9)	$ (5.4)	$ (4.2)