Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Segment Reporting Information [Line Items]
Interest income									$ 10,244	$ 10,641	$ 10,755
Interest expense	18,147	20,683	22,080	23,612	25,520	26,543	27,540	29,494	84,522	109,097	161,106
Provision for credit losses	0	2,000	4,000	4,000	4,000	6,000	10,000	10,000	10,000	30,000	250,229
Noninterest Income	31,227	46,698	44,741	31,587	32,899	29,112	34,335	29,982	154,253	126,328	136,965
Noninterest expense	89,589	89,408	87,607	88,649	85,875	86,620	91,587	88,308	355,253	352,390	395,045
Income before income taxes	17,745	30,598	32,044	13,291	14,833	11,328	7,555	5,417	93,678	39,133	(224,282)
Assets	9,236,910				9,193,237				9,236,910	9,193,237	9,493,169
Community Banking
Segment Reporting Information [Line Items]
Interest income									360,901	387,365	393,754
Interest expense									78,004	102,963	128,294
Net interest income									282,897	284,402	265,460
Provision for credit losses									9,980	56,507	177,232
Noninterest Income									46,433	76,337	67,499
Noninterest expense									266,486	295,139	332,557
Income before income taxes									52,864	9,093	(176,830)
Assets	8,754,170				9,219,398				8,754,170	9,219,398	7,643,294
Residential Construction Lending [Member]
Segment Reporting Information [Line Items]
Interest income											34,559
Interest expense											18,967
Net interest income											15,592
Provision for credit losses											64,767
Noninterest Income											60
Noninterest expense											7,291
Income before income taxes											(56,406)
Assets											25,562
Home Loan Division
Segment Reporting Information [Line Items]
Interest income									28,299	16,927	13,243
Interest expense									0	0	7,742
Net interest income									28,299	16,927	5,501
Provision for credit losses									20	71	8,230
Noninterest Income									108,391	48,865	65,099
Noninterest expense									92,742	58,979	36,785
Income before income taxes									43,928	6,742	25,585
Assets	477,127				2,594				477,127	2,594	1,811,601
Commercial
Segment Reporting Information [Line Items]
Interest income											3,573
Interest expense											0
Net interest income											3,573
Provision for credit losses											0
Noninterest Income											2,470
Noninterest expense											5,070
Income before income taxes											973
Assets											6,340
Other and Eliminations
Segment Reporting Information [Line Items]
Interest income									0	0	4
Interest expense									6,518	6,134	6,103
Net interest income									(6,518)	(6,134)	(6,099)
Provision for credit losses									0	(26,578)	0
Noninterest Income									(571)	1,126	1,837
Noninterest expense									(3,975)	(1,728)	13,342
Income before income taxes									(3,114)	23,298	(17,604)
Assets	5,613				(28,755)				5,613	(28,755)	6,372
Reportable Segment
Segment Reporting Information [Line Items]
Interest income									389,200	404,292	445,133
Interest expense									84,522	109,097	161,106
Net interest income									304,678	295,195	284,027
Provision for credit losses									10,000	30,000	250,229
Noninterest Income									154,253	126,328	136,965
Noninterest expense									355,253	352,390	395,045
Income before income taxes									$ 93,678	$ 39,133	$ (224,282)