Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2014

Below are the estimated useful lives for assets placed in service during 2014 and beyond:



	Estimated Useful Lives
Furniture, fixtures and equipment	3 to 5 years
Computer software	18 months to 7 years
Leasehold improvements	up to 5 years

Below are the amounts of internal-use software capitalized and amortized:



	Year ended December 31,
	2014		2013		2012
Amounts capitalized for internal-use computer software (including work-in-process)	$	34,053	$	18,360	$	17,341
Amounts expensed for amortization of internal-use computer software	18,661		18,830		20,694

Income available for common stockholders used to calculate earnings per share is as follows:



	Year ended December 31,
	2014		2013		2012
Net earnings attributable and available for common stockholders –Basic and Diluted	$	202,211	$	149,208	$	96,922

Weighted average common shares outstanding used to calculate earnings per share are as follows:



	Year ended December 31,
	2014	2013	2012
Weighted average common shares outstanding – Basic	38,890	38,946	38,840
Unvested restricted stock units	89	117	138
Stock options	21	40	114
Weighted average common shares outstanding – Diluted	39,000	39,103	39,092