Schedule II Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Valuation and Qualifying Accounts [Abstract]
Balance at beginning of year	[1]	$ 4,815	$ 3,397	$ 2,935
Charged to expense	[1]	7,002	4,822	2,317
Charged to other accounts	[1],[2]	1,470	881	0
Write-offs, net of recoveries	[1]	5,809	4,285	1,855
Balance at end of year	[1]	$ 7,478	$ 4,815	$ 3,397

[1] Additions to the allowance for doubtful accounts are charged to bad debt expense.

[2] Amounts represent opening balances from acquired businesses.