Income Taxes - Unrecognized Tax Benefits (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Total gross amount of unrecognized tax benefits that would impact effective tax rate	$ 400,000	$ 600,000
The expiration of the statute of limitations for certain tax positions in future years and expected settlement of certain tax audit that could impact unrecognized tax benefits	0
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at beginning of year	600,000	1,600,000	1,800,000
Increase in unrecognized tax benefits	0	200,000	0
Lapse of statute of limitations	(200,000)	(200,000)	(200,000)
Settlement	0	(1,000,000)	0
Balance at end of year	400,000	600,000	1,600,000
Income taxes benefit related to recovery of interest associated with expiration of statute of limitations for certain unrecognized tax position	200,000	100,000	100,000
Estimated interest and penalties related to unrecognized tax benefits	300,000	500,000
Estimated interest related to unrecognized tax benefits	200,000
Estimated penalties related to unrecognized tax benefits	$ 100,000