Stock Repurchase Program (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013	Mar. 08, 2012	May 02, 2011
Equity, Class of Treasury Stock [Line Items]
Treasury stock value acquired cost method			$ 18,146,000	$ 85,496,000
2011 Stock Repurchase Program [Member]
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program authorized amount						323,700,000	300,000,000
Treasury stock shares acquired	0	0	0	2,700,000
Treasury stock value acquired cost method	0	0	0	70,000,000
Stock repurchase program remaining authorized repurchase amount	$ 280,000,000		$ 280,000,000		$ 280,000,000