Goodwill and Intangible Assets Goodwill (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Goodwill [Roll Forward]
Balance at beginning of year	$ 536,005,000	$ 535,518,000	$ 534,862,000
Goodwill, Written off Related to Sale of Business Unit	(5,295,000)	0	0
Other goodwill additions, net	(54,000)	487,000	656,000
Balance at end of year	530,656,000	536,005,000	535,518,000
Goodwill	530,656,000	536,005,000	535,518,000
Subsidiaries [Member] | The Bank [Member]
Goodwill [Roll Forward]
Balance at end of year	167,600,000
Goodwill Impairment Test Adjusted Net Book Value Exceeding Fair Value Amount	54,200,000
Goodwill Impairment Test Adjusted Net Book Value Exceeding Fair Value Percent	12.00%
Goodwill	167,600,000
Subsidiaries [Member] | Columbia Bank [Member]
Goodwill [Roll Forward]
Balance at end of year	112,600,000
Goodwill Impairment Test Adjusted Net Book Value Exceeding Fair Value Amount	25,100,000
Goodwill Impairment Test Adjusted Net Book Value Exceeding Fair Value Percent	8.00%
Goodwill	112,600,000
Subsidiaries [Member] | FNB Bank [Member]
Goodwill [Roll Forward]
Balance at end of year	4,500,000
Goodwill	4,500,000
Subsidiaries [Member] | Three Reporting Units [Member]
Goodwill [Roll Forward]
Balance at beginning of year	16,600,000
Number Of Reporting Units	2
Goodwill Impairment Test Fair Value Exceeding Adjusted Net Book Value Percent		5.00%
Subsidiaries [Member] | Other Reporting Units [Member]
Goodwill [Roll Forward]
Balance at end of year		229,400,000
Goodwill		$ 229,400,000
Goodwill Impairment Test Fair Value Exceeding Adjusted Net Book Value Percent		21.00%