Goodwill and Other Intangible Assets (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Goodwill and Other Intangible Assets
Impairment loss on goodwill and other intangible assets			$ 0
Goodwill
Balance at the beginning of the period	192,575
Changes	633
Balance at the end of the period	193,208		192,575
Other Intangible Assets
Balance at the beginning of the period	55,075
Amortization	(23)
Balance at the end of the period	55,052		55,075
Amortization expense recognized on finite-lived intangible assets	23	23
VN segment
Goodwill
Balance at the end of the period	155,637	102,947
PC segment
Goodwill
Balance at the end of the period	37,571	30,974
Non-compete Agreements
Other Intangible Assets
Amortization	(23)
Balance at the end of the period	40		63
Non-compete Agreements | VN segment
Other Intangible Assets
Balance at the end of the period	8	31
Non-compete Agreements | PC segment
Other Intangible Assets
Balance at the end of the period	32	100
Certificates of Need and Licenses
Other Intangible Assets
Balance at the end of the period	38,321		38,321
Certificates of Need and Licenses | VN segment
Other Intangible Assets
Balance at the end of the period	37,541	8,781
Certificates of Need and Licenses | PC segment
Other Intangible Assets
Balance at the end of the period	780	610
Trade Names
Other Intangible Assets
Balance at the end of the period	16,691		16,691
Trade Names | VN segment
Other Intangible Assets
Balance at the end of the period	13,311	7,701
Trade Names | PC segment
Other Intangible Assets
Balance at the end of the period	$ 3,380	$ 2,720