Parent Holding Company Information (Condensed) (Details 1) (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
Expenses
Compensation and employee benefits									$ 95,373	$ 85,691	$ 87,728
Federal and state income tax expense (benefit)	(5,853)	(4,760)	(3,843)	(4,621)	(2,408)	5,353	(826)	(1,838)	(19,077)	281	(7,343)
Net Income	20,758	19,444	18,981	16,333	14,348	(19,048)	11,886	10,285	75,516	17,471	42,330
Parent Company [Member]
Income
Dividends from subsidiaries									78,209	43,450	31,350
Other income									566	864	3,730
Intercompany charges for services									16,041	14,438	13,977
Total income									94,816	58,752	49,057
Expenses
Compensation and employee benefits									12,392	9,185	8,287
Other operating expenses									10,267	11,827	12,990
Total expenses									22,659	21,012	21,277
Income before income tax benefit and equity in undistributed net income of subsidiaries									72,157	37,740	27,780
Federal and state income tax expense (benefit)									2,319	2,176	1,374
Income before equity in undistributed net income of subsidiaries									74,476	39,916	29,154
Equity in undistributed net income (loss) of subsidiaries									1,040	(22,825)	13,558
Net Income									$ 75,516	$ 17,091	$ 42,712