SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) (USD $) Share data in Thousands, except Per Share data	3 Months Ended		9 Months Ended			3 Months Ended	5 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Dec. 31, 2010	Sep. 30, 2011 Surety	Sep. 30, 2011 Surety	Dec. 31, 2010 Surety	Apr. 30, 2011 Contractors Bonding and Insurance Company (CBIC)
ADOPTED ACCOUNTING STANDARDS
Maximum carrying amount of reporting unit for goodwill impairment testing	$ 0		$ 0
Goodwill
Goodwill and intangibles	60,733,000		60,733,000		26,214,000	26,200,000	26,200,000	26,200,000	34,500,000
Amortization of intangible assets						200,000	300,000
Basic EPS, Income (Numerator)
Income available to common shareholders	26,057,000	27,965,000	99,899,000	87,180,000
Diluted EPS, Income (Numerator)
Income available to common shareholders	$ 26,057,000	$ 27,965,000	$ 99,899,000	$ 87,180,000
Basic EPS, Shares (Denominator)
Number of shares outstanding	21,089	20,931	21,063	21,043
Effect of Dilutive Securities, Shares (Denominator)
Stock options (in shares)	246	159	261	190
Diluted EPS, Shares (Denominator)
Number of shares outstanding	21,335	21,090	21,324	21,233
Basic EPS, Per Share Amount
Basic earnings per share (in dollars per share)	$ 1.24	$ 1.34	$ 4.74	$ 4.14
Diluted EPS, Per Share Amount
Diluted earnings per share (in dollars per share)	$ 1.22	$ 1.33	$ 4.68	$ 4.11