Fair Values of Financial and Nonfinancial Instruments (Details 2) (USD $)	6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended			12 Months Ended		6 Months Ended	12 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013 Mortgage interest rate lock commitments ("IRLCs")	Jun. 30, 2012 Mortgage interest rate lock commitments ("IRLCs")	Jun. 30, 2013 Mortgage interest rate lock commitments ("IRLCs")	Jun. 30, 2012 Mortgage interest rate lock commitments ("IRLCs")	Jun. 30, 2013 Mortgage loans held-for-sale	Jun. 30, 2012 Mortgage loans held-for-sale	Jun. 30, 2013 Mortgage loans held-for-sale	Jun. 30, 2012 Mortgage loans held-for-sale	Jun. 30, 2013 Measured on a non-recurring basis Other assets held-for-sale	Dec. 31, 2012 Measured on a non-recurring basis Other assets held-for-sale	Dec. 31, 2012 Measured on a non-recurring basis Investments in joint ventures	Jun. 30, 2013 Measured on a non-recurring basis Housing inventory	Dec. 31, 2012 Measured on a non-recurring basis Housing inventory
Financial and nonfinancial instruments
(Losses) gains realized on the IRLC pipeline			$ (4,200,000)	$ 1,500,000	$ (2,900,000)	$ 2,100,000
Gains (losses) from instruments used to hedge IRLCs			9,600,000	(3,400,000)	10,300,000	(3,900,000)
Gains on loan sales							3,600,000	6,800,000	8,300,000	10,100,000
Fair value of impaired assets											257,000	263,000	1,300,000		2,900,000
Impairment charges	$ 561,000	$ 2,454,000									$ 39,000	$ 41,000	$ 40,000	$ 0	$ 1,900,000