Stock-based Compensation - Director Deferred Compensation (Details) - Director - shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Beginning balance, Director Deferred Stock (in shares)	135,722
New shares deferred (in shares)	14,722
Issued (in shares)	(7,531)	(7,178)	(12,909)
Ending balance, Director Deferred Stock (in shares)	142,913	135,722