Fair Value (Details 5) (Nonrecurring basis, USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013 Mortgage servicing rights	Sep. 30, 2013 Mortgage servicing rights Minimum	Sep. 30, 2013 Mortgage servicing rights Maximum	Sep. 30, 2013 Level 3	Dec. 31, 2012 Level 3	Sep. 30, 2013 Total	Dec. 31, 2012 Total
Financial statement items measured at fair value on a nonrecurring basis
Mortgage servicing rights at lower of amortized cost or fair value								$ 102,116	$ 51,180	$ 102,116	$ 51,180
Total assets								102,116	51,180	102,116	51,180
Total gains (losses) on assets measured at estimated fair values on a nonrecurring basis
Mortgage servicing rights at lower of amortized cost or fair value	(1,164)	(1,000)	(521)	(1,784)
Total gains on assets measured at estimated fair values on a nonrecurring basis	$ (1,164)	$ (1,000)	$ (521)	$ (1,784)
Additional disclosures
Note basis points used for grouping of fixed-rate mortgage loan pools for impairment analysis					0.50%
Interest rate threshold for grouping of fixed-rate mortgage loans into pools for impairment analysis						3.00%	4.50%
Maximum initial interest rate threshold for grouping of adjustable rate mortgage loans into a single pool for impairment analysis					4.50%