Stockholders' Equity - Summary of activity under stock-based incentive plans (Details)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Restricted Stock All [Member]
Summary of the activity under the incentive plans
Stock-based awards, beginning of period	1,788,168	1,770,061
Granted	101,522	66,787
Vested	(34,365)	(23,775)
Forfeited	0	0
Stock-based awards, end of period	1,855,325	1,813,073
Stock Incentive Plan [Member]
Summary of the activity under the incentive plans
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures	101,522	66,787
Stock Incentive Plan [Member] | Restricted Stock [Member]
Summary of the activity under the incentive plans
Shares Paid for Tax Withholding for Share Based Compensation	9,974	6,061