CONDENSED CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (Parenthetical) $ in Thousands	6 Months Ended
	Jun. 30, 2017 USD ($) $ / shares shares
Statement of Stockholders' Equity [Abstract]
Pension and other postretirement adjustments, tax	$ 1,146
Amortization of forward starting swaps, tax	$ 1,218
Issuance of common stock from performance share units and exercise of stock options (in shares) | shares	335,902
Issuance of common stock from exercise of stock options and deferred compensation plans, tax amount	$ 4,998
Repurchase of common stock (in shares) | shares	106,000
Cash dividends declared, per common share outstanding (in dollars per share) | $ / shares	$ 0.74