CONSOLIDATED STATEMENTS OF EQUITY (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Stockholders' Equity [Abstract]
Tax benefit (expense) on change in retirement obligations, tax	$ 53	$ 1,553	$ 3,076
Tax benefit from change on derivatives designated as cash flow hedges, tax	$ 1,369	$ 1,445	$ 1,469
Issuance of common stock from issuance of unvested shares, exercise of stock options and deferred compensation plans (in shares)	688,563	696,133	583,385
Repurchase of common stock (in shares)	876,423	388,953	1,273,961
Deferred compensation plan, tax	$ 4,967	$ 5,493	$ 4,267
Cash dividends declared, per common share outstanding (in dollars per share)	$ 2.00	$ 2.00	$ 1.72