RELATED-PARTY TRANSACTIONS - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
Mr. Johnson
Related Party Transaction [Line Items]
Shares returned, to satisfy withholding obligations relating federal, state or other taxes	$ 209,208	$ 205,316
Mr. Elders
Related Party Transaction [Line Items]
Shares returned, to satisfy withholding obligations relating federal, state or other taxes	16,137	12,887
Mr. Carlson
Related Party Transaction [Line Items]
Shares returned, to satisfy withholding obligations relating federal, state or other taxes	14,654	13,137
Mr. Scott V. Cummins
Related Party Transaction [Line Items]
Shares returned, to satisfy withholding obligations relating federal, state or other taxes	10,302	9,165
Ms. Hinrichs
Related Party Transaction [Line Items]
Shares returned, to satisfy withholding obligations relating federal, state or other taxes	65,975	119,901
Mr. Houser
Related Party Transaction [Line Items]
Shares returned, to satisfy withholding obligations relating federal, state or other taxes	15,577	19,452
Mr. McCormack
Related Party Transaction [Line Items]
Shares returned, to satisfy withholding obligations relating federal, state or other taxes	37,232	29,822
Mr. Mitchell
Related Party Transaction [Line Items]
Shares returned, to satisfy withholding obligations relating federal, state or other taxes	10,057	14,021
Mr. Roll
Related Party Transaction [Line Items]
Shares returned, to satisfy withholding obligations relating federal, state or other taxes	21,297	21,479
Mr. Nesser
Related Party Transaction [Line Items]
Shares returned, to satisfy withholding obligations relating federal, state or other taxes		$ 85,423