Earnings Per Share (Details) - shares		3 Months Ended		9 Months Ended
		Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Earnings Per Share [Abstract]
Weighted-average common shares – basic		145,231,160	148,855,336	145,228,755	152,231,060
Deferred and performance stock awards (in shares)		438,000	321,000	372,000	268,000
Weighted-average common shares outstanding – diluted	[1]	145,669,237	149,176,207	145,601,026	152,499,430
Common stock, shares outstanding		145,233,753		145,233,753		145,511,644

[1] Due to repurchases of common stock during the current year, Piedmont has 145,233,753 shares of common stock outstanding as of September 30, 2016.