Summary of Significant Accounting Policies (Narrative) (Details) (USD $) Share data in Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Business Combination, Consideration Transferred	$ 82,400,000
Unfunded settlements	5,100,000	3,700,000
Intangible asset useful life	20 years
Intangible assets, acquired cost (gross)	259,000,000	259,000,000
Intangible assets, accumulated amortization	135,900,000	122,900,000
Intangible assets amortization expense	13,033,000	13,100,000	13,100,000
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months	12,900,000
Future Amortization Expense, Year Two	12,900,000
Future Amortization Expense, Year Three	12,900,000
Future Amortization Expense, Year Four	12,900,000
Future Amortization Expense, Year Five	12,900,000
Intangible asset impairment expense	0	0	0
Property and equipment, net	75,219,000	53,051,000
Property and equipment, accumulated depreciation	192,200,000	182,000,000
Depreciation Expense	26,800,000	18,500,000	16,900,000
Advertising Expense	41,800,000	42,400,000	45,800,000
Employee benefit plan company contributions	12,100,000	11,000,000	9,400,000
Charges related to contractual dispute		41,200,000
Provision for Doubtful Accounts			5,100,000
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	6.6	9.6	16.6
Number of VIEs requiring consolidation	0	0
Land, not owned, under option agreements	30,186,000	24,024,000
Liability for land, not owned, under option agreements	30,186,000	24,024,000
Residential mortgage loans available-for-sale	339,531,000	287,933,000
Residential mortgage loans available-for-sale aggregate outstanding principal balance	327,400,000	278,100,000
Net gain (loss) from change in fair value	1,700,000	(1,200,000)
Net gains from the sale of mortgages	67,200,000	80,300,000	109,200,000
Loans held for investment, net	12,500,000	11,000,000
Days past contractual term once loans no longer accrue interest income	90 days
Variability in future cash flows of derivative instruments in days	75 days
Furniture and Fixtures [Member]
Property and equipment, useful life	2 years
Minimum [Member]
Period of Reimbursement of Payments on Loan Prepay in Days	90 days
Minimum [Member] | Equipment [Member]
Property and equipment, useful life	3 years
Maximum [Member]
Period of Reimbursement of Payments on Loan Prepay in Days	120 days
Maximum [Member] | Equipment [Member]
Property and equipment, useful life	10 years
Financial Services [Member]
Interest income on mortgage loans	7,200,000	7,500,000	6,000,000
Interest Rate Lock Commitments [Member]
Derivative, notional amount	146,100,000	175,700,000
Forward Contracts [Member]
Derivative, notional amount	371,000,000	381,500,000
Whole Loan Commitments [Member]
Derivative, notional amount	$ 63,500,000	$ 31,700,000