Net Income Per Share Reconciliation of Weighted Average Common Shares Outstanding (Details) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Weighted Average Number of Shares Outstanding Reconciliation [Abstract]
Weighted average shares outstanding (basic)	176,433	188,139	177,446	188,799
Impact of common stock equivalents	1,098	1,043	1,042	1,033
Weighted average shares outstanding (diluted)	177,531	189,182	178,488	189,832