Earnings Per Share (Details) - shares		3 Months Ended		9 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Earnings Per Share [Abstract]
Weighted-average common shares – basic		148,855,336	154,325,073	152,231,060	154,495,761
Deferred stock awards (in shares)		321,000	236,000	268,000	169,000
Weighted-average common shares outstanding – diluted	[1]	149,176,207	154,561,362	152,499,430	154,664,834
Common stock, shares outstanding		145,633,869		145,633,869		154,324,089

[1] Due to repurchases of common stock during the nine months ended September 30, 2015, Piedmont has 145,633,869 shares of common stock outstanding as of September 30, 2015.