Acquisitions - Fair Values of Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Jul. 22, 2015	Apr. 01, 2015	Dec. 31, 2014	Dec. 31, 2013
Fair values of the assets acquired and the liabilities assumed
Goodwill	$ 616,780	$ 585,787			$ 106,261	$ 27,966
2015 Journal acquisition
Fair values of the assets acquired and the liabilities assumed
Cash				$ 2,529
Accounts receivable				47,978
Other assets				2,236
Equipment and software				123,264
Intangible assets				294,800
Goodwill				456,440
Other long-term assets				6,350
Assets held for sale				14,500
Total assets acquired				948,097
Accounts payable and accrued liabilities				38,107
Employee benefit obligations				85,261
Long-term deferred tax liability				57,112
Long-term debt				126,873
Other long-term liabilities				4,744
Net purchase price				$ 636,000
2015 Midroll acquisition
Fair values of the assets acquired and the liabilities assumed
Cash			$ 635
Accounts receivable			2,925
Intangible assets			10,700
Goodwill			45,586
Other long-term assets			482
Total assets acquired			60,328
Current liabilities			3,365
Net purchase price			$ 56,963