Fair Value (Schedule of Fair Value of Predominantly Bank Trust Preferred) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011
Financing Receivable, Recorded Investment [Line Items]
Fair value of bank trust preferred	739,315
Percentage of total fair value by vintage	100.00%
AAA [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of total fair value	78.10%
A [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of total fair value	21.60%
BBB [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of total fair value	0.30%
2001 [Member]
Financing Receivable, Recorded Investment [Line Items]
Fair value of bank trust preferred	67,252
Percentage of total fair value by vintage	9.10%
2001 [Member] | AAA [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of total fair value	7.90%
2001 [Member] | A [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of total fair value	1.10%
2001 [Member] | BBB [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of total fair value	0.10%
2002 [Member]
Financing Receivable, Recorded Investment [Line Items]
Fair value of bank trust preferred	226,421
Percentage of total fair value by vintage	30.70%
2002 [Member] | AAA [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of total fair value	28.40%
2002 [Member] | A [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of total fair value	2.30%
2002 [Member] | BBB [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of total fair value	0.00%
2003 [Member]
Financing Receivable, Recorded Investment [Line Items]
Fair value of bank trust preferred	252,677
Percentage of total fair value by vintage	34.20%
2003 [Member] | AAA [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of total fair value	25.60%
2003 [Member] | A [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of total fair value	8.60%
2003 [Member] | BBB [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of total fair value	0.00%
2004 [Member]
Financing Receivable, Recorded Investment [Line Items]
Fair value of bank trust preferred	111,611
Percentage of total fair value by vintage	15.10%
2004 [Member] | AAA [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of total fair value	7.80%
2004 [Member] | A [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of total fair value	7.30%
2004 [Member] | BBB [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of total fair value	0.00%
2005 [Member]
Financing Receivable, Recorded Investment [Line Items]
Fair value of bank trust preferred	9,909
Percentage of total fair value by vintage	1.30%
2005 [Member] | AAA [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of total fair value	1.00%
2005 [Member] | A [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of total fair value	0.30%
2005 [Member] | BBB [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of total fair value	0.00%
2006 [Member]
Financing Receivable, Recorded Investment [Line Items]
Fair value of bank trust preferred	37,272
Percentage of total fair value by vintage	5.00%
2006 [Member] | AAA [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of total fair value	2.80%
2006 [Member] | A [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of total fair value	2.00%
2006 [Member] | BBB [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of total fair value	0.20%
2007 [Member]
Financing Receivable, Recorded Investment [Line Items]
Fair value of bank trust preferred	34,173
Percentage of total fair value by vintage	4.60%
2007 [Member] | AAA [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of total fair value	4.60%
2007 [Member] | A [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of total fair value	0.00%
2007 [Member] | BBB [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of total fair value	0.00%