Long-Term Debt (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2011
Components of long-term debt
Total long-term debt	$ 852,481	$ 854,185	$ 855,670
Citizens [Member] | 5.75% subordinated notes due February 2013 [Member]
Components of long-term debt
Total long-term debt	17,214	17,101
Citizens [Member] | Variable rate junior subordinated debenture due June 2033 [Member]
Components of long-term debt
Total long-term debt	25,774	25,774
Citizens [Member] | 7.50% junior subordinated debentures due September 2066 [Member]
Components of long-term debt
Total long-term debt	48,677	48,677
Subsidiaries [Member] | FHLB advances [Member]
Components of long-term debt
Total long-term debt	656,700	658,484
Subsidiaries [Member] | Other borrowed funds [Member]
Components of long-term debt
Total long-term debt	$ 104,116	$ 104,149