CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Mar. 31, 2013	Jun. 30, 2014	Jun. 30, 2013
Net loss arising from period related to defined benefit pension plan, tax	$ 0	$ 0	$ 0	$ (119)
Amortization of prior service cost included in net periodic pension cost, tax	0	0	0	28
Partial settlement of pension plan liability, tax	0	0	0	336
Unrealized gains (losses) on change in fair value of interest rate swap contracts, tax	0	217	110	350
Reclassification adjustment for (gains) losses included in net income, tax	$ 0	$ (113)	$ (55)	$ (179)