CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Statement of Comprehensive Income [Abstract]
Net reclassification adjustments for amounts recognized in net income as a component of net periodic benefit cost, tax expense	$ 1,349	$ 1,840	$ 2,698	$ 3,648