Income Taxes Income Taxes Discussion (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Investments, Owned, Federal Income Tax Note [Line Items]
Unrecognized Tax Benefits, Period Increase (Decrease)				$ 1,600,000
Effective Income Tax Rate Reconciliation, Percent			31.90%	34.40%
Income tax expense	$ 10,333,000	$ 10,701,000	$ 17,471,000	$ 16,741,000
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate			35.00%	35.00%
change in interpretation of tax law with respect to certain positions previously taken [Member]
Investments, Owned, Federal Income Tax Note [Line Items]
Significant Change in Unrecognized Tax Benefits, Nature of Event				a change in the interpretation of tax law with respect to certain tax positions taken on previously filed tax returns and was subsequently released due to settlements with taxing authorities during the quarter ended December 31, 2013.