Fair Value (Details 4) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Fair value
Total fair value	$ 530,248	$ 448,384
Mortgage loans held for sale at fair value
Fair value
Current through 89 days delinquent	529,244	447,889
90 or more days delinquent	1,004	495
Total fair value	530,248	448,384
Principal amount due upon maturity
Current through 89 days delinquent	496,853	418,650
90 or more days delinquent	1,297	623
Total principal amount due upon maturity	498,150	419,273
Difference
Current through 89 days delinquent	32,391	29,239
90 or more days delinquent	(293)	(128)
Total difference	$ 32,098	$ 29,111