Shareholders' Equity (Tables)

12 Months Ended

Dec. 31, 2018

Equity [Abstract]

Schedule of Stock Repurchase Activity

A summary of the stock repurchase activity under the stock repurchase program, reported based on the trade date, is summarized as follows:

(DOLLARS IN THOUSANDS)	Shares Repurchased	Weighted- Average Price per Share		Dollar Amount Repurchased
Year Ended December 31, 2018	108,109	$	143.15	15,475
Year Ended December 31, 2017	459,264	126.44		58,069
Year Ended December 31, 2016	1,058,018	124.01		127,443