Leasing Arrangements (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Future minimum capital lease payments
2014	$ 1,732,000
2015	1,732,000
2016	1,732,000
2017	1,732,000
2018	2,022,000
Subsequent to 2018	5,517,000
Total minimum lease payments	14,467,000
Amounts representing interest	1,400,000
Present value of net minimum lease payments	13,067,000
Current maturities	1,430,000
Long-term capital lease obligation	11,637,000
Future minimum operating lease payments
2014	35,577,000
2015	28,780,000
2016	23,035,000
2017	15,915,000
2018	12,118,000
Subsequent to 2018	28,659,000
Total minimum lease payments	144,084,000
Rental expense for all operating leases
Rental expense for all operating leases	45,000,000	42,900,000	40,900,000
Rental income on subleases of equipment	600,000	600,000	800,000
Assets recorded under capital leases
Plant and equipment	14,509,000	12,307,000
Less accumulated amortization	1,650,000	726,000
Assets recorded under capital leases	12,859,000	11,581,000
Capital lease obligations with lease agreements to acquire plant and equipment	$ 2,200,000	$ 9,300,000	$ 3,000,000