Employee Benefit Plans, Assumptions and Resulting Estimates of Fair Value (Details) (USD $)	6 Months Ended
	Jun. 30, 2014		Jun. 30, 2013
ESPP [Member]
Estimates of Fair Value
Volatility	33.00%	[1]	36.00%	[1]
Risk-free interest rate	0.10%	[1]	0.10%	[1]
Expected life (years)	6 months	[1]	6 months	[1]
Dividend yield	0.00%	[1]	0.00%	[1]
Weighted-average fair value per share (in dollars per share)	$ 6.37	[1]	$ 5.63	[1]
Market-based RSUs [Member]
Estimates of Fair Value
Volatility	36.00%	[2]
Risk-free interest rate	1.60%	[2]
Weighted-average fair value per share (in dollars per share)	$ 0	[2]
Market-based RSUs [Member] | Minimum [Member]
Estimates of Fair Value
Dividend yield	0.00%	[2]
Market-based RSUs [Member] | Maximum [Member]
Estimates of Fair Value
Dividend yield	1.50%	[2]

[1] The Black-Scholes-Merton option-pricing model is utilized to estimate the fair value of ESPP.

[2] The fair value of market-based RSUs utilizes a Monte Carlo valuation methodology. The Company amortizes the fair value of these awards over the derived service period adjusted for estimated forfeitures for each separately vesting tranche of the award. Provided that the derived service is rendered, the total fair value of the market-based RSUs at the date of grant is recognized as compensation expense even if the market condition is not achieved. However, the number of shares that ultimately vest can vary significantly with the performance of the specified market criteria.