Fair Values of Financial and Nonfinancial Instruments (Details 2) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Nonfinancial instruments measured on nonrecurring basis
Impairment charges	$ 6,262,000	$ 17,319,000	$ 41,938,000
Mortgage interest rate lock commitments ("IRLCs")
Nonfinancial instruments measured on nonrecurring basis
Gain realized on conversion to loans	25,000,000	16,300,000	18,400,000
Increase (decrease) in fair value of the pipeline of IRLCs	1,400,000	1,900,000	(559,000)
Offsetting gains (losses) from instruments used to hedge IRLCs	(8,100,000)	(7,300,000)	(6,100,000)
Measured on a non-recurring basis | Level 3
Nonfinancial instruments measured on nonrecurring basis
Fair value of impaired assets	4,486,000	11,487,000
Measured on a non-recurring basis | Level 3 | Housing inventory and inventory held-for-sale
Nonfinancial instruments measured on nonrecurring basis
Fair value of impaired assets	2,923,000	9,121,000
Impairment charges	1,900,000	9,500,000
Measured on a non-recurring basis | Level 3 | Other assets held-for-sale and investments in joint ventures
Nonfinancial instruments measured on nonrecurring basis
Fair value of impaired assets	1,563,000	2,366,000
Measured on a non-recurring basis | Level 3 | Other assets held-for-sale
Nonfinancial instruments measured on nonrecurring basis
Fair value of impaired assets	263,000	973,000
Impairment charges	41,000	35,000
Measured on a non-recurring basis | Level 3 | Investments in joint ventures
Nonfinancial instruments measured on nonrecurring basis
Fair value of impaired assets	1,300,000	1,400,000
Impairment charges	$ 40,000	$ 2,000,000