Summary of Significant Accounting Policies - Earnings Per Share (Details)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	251,667	342,448
Restricted Shares [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Incremental Common Shares Attributable to Share-based Payment Arrangements	245,828	293,021	219,911
Stock Options [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Incremental Common Shares Attributable to Share-based Payment Arrangements	141,656	176,428	208,175
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	251,667	342,448	675,665