Earnings Per Share (Details) - shares	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Weighted Average Number of Shares Outstanding, Diluted [Abstract]
Weighted Average Number of Shares Outstanding, Basic	82,253,470	82,349,024
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements	102,578	95,434
Weighted Average Number of Shares Outstanding, Diluted	82,356,048	82,444,458